Hello, thanks for the welcome and thanks for replying.
I have no idea why he changed his name, it is so confusing, he married in Co. Sligo 1920/21using the name Evans.
When he moved back to Wales a few years later his children were registered as Davies yet baptised as Evans.
My dad always thought Evans was our surname but said he had heard that it may have been Davies. Incidentally my grandad's death certificate has him as Davies.
Oh and just to confuse matters even more he married using the name John but everywhere else he was either David John or David!
I have no idea where to go from here, there was a rumour that he may have joined the Black and Tans after the war so maybe this was his secret as he married a local Catholic girl.