Fathers on marriage certificates weren’t always noted as deceased.
Often just the fathers name was given so the fact a son in 1921 didn’t say father deceased doesn’t mean he wasn’t.
Have you checked out Scottish births for him. Why would he be sent to Dundee?
Checked Scottish Births and deaths with no success. He was arrested in Dundee and sent to Norwich to face the desertion charge brought by his legal wife - my GGM Florence Gertrude Swan - he was then sent back to Dundee to face the bigamy charge for which he was subsequently imprisoned for 30 days at Dundee.
I've been unable to trace him following his release from prison.
1911 welsh census has a Peter boarding in house as a deep sea fisher man - status married. POB Liverpool. There is a discrepancy over his DOB from Marriage Record, Census returns and Prison record. There is nothing to confirm that this is 'our' Peter, however the census indicates that Peter spoke English and Welsh - which gives some credence to him actually having possibly been brought up in Wales rather than Liverpool. One of my cousins in the US spoke to one of Peter's grandsons before he died, and he recollected that he was told his grandfather was Welsh but had never met him as his parents emigrated to Canada, and he was born in Canada.
1924 register of electors a Peter is listed at John Cory Sailor's Rest and Bethel, Charles St, Milford Haven - he would have been around 65 years old at the time
1926 register of electors a Peter Walker at 15 Marblehall Terrace, Milford Haven - renting one furnished room - this would have made him around 67 years old.
I've not been able to find any death record in Wales for a Peter of anything like the correct age.
My father was born in 1920 and the only thing I recollect him saying was that his mother had told him that her father - Peter Walker - was 'a wrong un'
