Thanks Heywood, looks like we have found these records at around the same time, thanks, its always good to know someone else finds the same!
There is a death record in Dublin, 1889 for Mary Jane Dunbar, wife of a photographer registered by her son, Henry Dunbar. She seems to have been buried at Mount Jerome, I've yet to find if those records are available online.
Still got a fair bit more firkling to do but its adds extra weight to the death registration in Toronto - though still stumped on the cause of death. and I've found a possible passenger list in 1905 for a T Dunbar and a J Dunbar going to Canada, if his brother John went with him, that would explain the accuracy of the birth place and also tie in with his widow back in England getting the news and applying for admin.
I'll keep on plugging away at it gather everything I have together and as long as I end up with enough checking points its all now looking likely.
I'm actually researching Thomas' daughters, they were orphaned when their Mum died in 1907 , they and their brother ended up in 3 different orphanages so its taking me a long time.
Boo