Hi saw your message and realised your James Wilson was my grandmother's brother. Sorry I cant help with regard to what happened to the shops but I can give you some family background with dates etc etc.
I was confused when I read your message because we always thought John was the eldest son and it seems your relative James was the eldest and we knew John had lived in London. My mother is from Lancashire lived in Belfast from 1949 and John had left Belfast by then. My Mother who is 85 thought James lived in Lisburn and had a farm. Incidentally John died in London either late 1950s or very early 1960s and he died penniless. As far as I know there was seven children as mentioned on the 1911 census. The great grandmother gave birth to 11 of which 7 lived namely. James, John, Annie, Jane (known as Jean), twins Elizabeth (Lilly) and Mary (May) and finally Robert (Bob). My great grandfather James died in 1923 and the great grandmother died in 1935 the address on her death certification is 429 Lisburn Road. We were told it the business generated a very good income because they had trawlers in the 1920s and the telephone number for 429 Lisburn Road is listed in the 1913 Belfast telephone directory which you can view if you visit Lennon Wylie site which gives street directories for all belfast roughly from 1890s up to approx 1913. The other shop in question was on the Albertbridge Road, Nos 74 and 76. The name above the shop was actually John Wilson and I have a photograph of that shop. We also have photographs of the family in their younger days. Looking at dates your relative would have been approximately 18 when the twins were born and the brother John was about 10. He is still living at home in the 1911 census. Incidentally your relative my grans brother was married in the October 1911 and my gran was married a month earlier in the Sept same year. Her sister Mary (known as May) was married the year before. Jane (or we called her Auntie Jean) never married. My mother thinks Annie married and become a Johnston (not sure which spelling is correct for that name) nor do we know anything about Robert.
If you are still interested I can give you more information dates of marriages etc and I also have a photograph which says James Wilson on the back, however, the gentleman is in a military uniform so this may not be the correct James Wilson.
It may be that the great granparents left wills in which case I know the dates but will need to find them. I just found them recently on a free site for Belfast burials.
Hope some of this is of interest to you best wishes
I found this thread whilst having quick Google after speaking to my mum - I think James is my great grandfather, my mum recalls visiting Jimmy Wilson close to Lisburn and he apparently owned 3 fish shops and later moved to London - she recall playing with her cousins and there were 3 sons that were treated like princes - my grandmother apparently moved from London grew up in Ireland and moved from Belfast to Scotland.
