Barking up the wrong tree!

I have been dealing with an interesting issue lately involving my husbands grandfathers family tree. Working with details I had been given about his life I was happily researching what I believed to be his family.  I had his birth certificate so I was working from a primary source and was steadily adding facts, dates, people and places and quite happy with the results for a while.
I had been told that he spent a good part of his childhood in Glasgow and that he had served in the First World War and had been a Prisoner of War.  Then in the 1920's he took up a job as a Prison Warder in Malaya.  He became engaged and in 1928 married Violet Helen Marguerite Murray in Singapore.  The stories were that the marriage was greatly affected by the death of their oldest son and broke down although they didn't divorce.  When Singapore fell in 1942 he was working as a Prison Officer at Changi and while he got his wife and son Ronald on a boat to England he remained behind.  He became a Prisoner at his former work place while his wife and son made it to England and lived in Barrow in Furness during the war.  After the war a skeletal William Allardice Martin who was affected by Beriberi joined his family in Barrow in Furness but subsequently returned to Singapore.  He died in Singapore fairly young, I was told as a result of health issues related to his time as a Prisoner of War.
Starting with the birth certificate I began to assemble details of his life in the full knowledge that family stories often embellish the truth.  His engagement notice here stated that his parents were the late Mr. and Mrs. Martin of Scotland. So from this I gathered that his parents had died before 1927 in Scotland.  The article describing his wedding to Violet in 1928 here confirmed he worked for the Prison Department, Straits Settlements and that he was an only son but they had his father as W.W. Martin of Glasgow not W.A. Martin as stated on his birth certificate.  I found passenger lists that documented his and his families travels between Straits Settlements and England during the 1930's and 40's that revealed some connection with Barrow in Furness as early as 1934.  Their son also named William died in Barrow in Furness in 1934.  Violet and their two boys William and Ronald were in England at this time while William was still working in the Straits Settlements.  I also found the passenger list from 1945 with him returning to England after the war on board the 'Tegelberg' with his next of kin listed at his wife Violet who was residing in Barrow in Furness.  In June 1946 he departed England to return to Singapore on board the 'Mauretania'.  His death notice here just three years after his return to Singapore confirmed that he died quite soon after the war however the age in the article was incorrect as his birth certificate had him born in 1900 not 1902.
Then when I started researching deeper into his family connections things began to unravel.  I had his parents as William Alexander Martin and Elizabeth Martin nee Allardice who married in Scotland in 1898.  I found that they emigrated to Canada in 1902/1903 with their son William Allardice Martin and daughter Jessie. This is where my suspicions started to grow, family stories had William Allardice Martin growing up for some time in Glasgow yet the William Allardice Martin I was researching was a toddler when the family moved to Canada.  While I can find him travelling between Scotland and Canada at times it is not for lengthy periods.  Then while I could find a World War One Canadian service record for William Alexander Martin, the family stories of William Allardice Martin serving in World War One and being a Prisoner of War were not verifiable as my research was showing that William Allardice Martin was in Canada at the time.
The questions continued to build up!  Were the Glasgow childhood stories true?  Did he serve in the First World War? If he did was he using another name? How did he get from Canada to Malaya? What was the connection with Barrow in Furness?
I found William Alexander Martins death certificate online through Familysearch here and Elizabeth Martins death certificate here.  So his parents didn't die before 1927!  Then recently I found newspaper articles from Canada that gave me more details about William Alexander Martin, his wife Elizabeth, daughter Jessie and son William Allardice Martin.  Elizabeth Martins obituary here and William Alexander Martins obituary here both stated that that their son William lived in Calgary, Canada.  Now my William Allardice Martin was certainly not living in Calgary, Canada in either 1945 or 1946, something was definitely amiss.  He was an only son and the birth dates were within error range but the locations were completely out and what was the connection with Barrow in Furness?  Could there have been a fall out with his family and they really didn't know where he was? Was the William Allardice Martin I was researching using some other persons identity, if so why?
The answers have proved to be much more mundane!  Yesterday my sister in law sent me copies of her Grandmother Violets birth, death and marriage certificates and it was through these my suspicions were proved to be correct.  My husbands grandfather was not the same William Allardice Martin from the birth certificate.  At some stage someone had received the wrong birth certificate and passed it down through the family as being their William Allardice Martins.  On Violet and Williams marriage certificate his parents are listed as William and Margaret Martin not William and Elizabeth Martin.  Further quick digging has shown me that there is a William and Margaret Martin with a connection to Barrow in Furness who had a son William born in Glasgow in the early 1900's who was an only living son.
So it seems I have been barking up the wrong family tree since I first began my research back in 1996.  I had done the right thing and taken information from a primary source but it was not the correct birth certificate for the William Allardice Martin I was researching.  I did enjoy researching William Allardice Martins tree and have amassed a fair bit of information on them going back a number of generations on each side, the only problem is it wasn't the William Allardice Martin I was wanting to research in the first place.  Oh well you never know with genealogy and Scottish connections being what they are there may be some cross over between the right William Allardice Martins tree and the wrong William Allardice Martin tree at some point in the future and I will be able to use what I already have on them then.
Now I have well and truly learned to trust my instincts and if something feels wrong it probably is, you cannot make the facts fit the story! Primary sources are extremely important and birth certificates do tend to be pretty accurate but you need to make sure it is the correct primary source in the first place. I am off to do some revisions to my tree and start my research on this line all over again!