Bill
The numbering in the street was consecutive, so next door would be 12 or 14.
I noticed, on looking for your uncle, that William Goodchild is also listed in 1938-1940 as a cycle dealer at no 19 Sun St. wouldn’t think there would be two different ones so close, so he had a second string to his bow. In 1949 and 1950 J.A.Williams occupied no 12 listed as a cycle dealer. In 1956 he is listed as the occupant of no13 , your uncles old shop, as a hardware dealer. He (and no 13) has gone by 1962.
J.A.Williams is not listed on the electoral roll at no 12 or 13 in 1945 or 1950. there is however a J.A.Williams on the roll in 1950 at no 6 back 10 sun St. (though J.A.Williams wouldn’t be a very unusual name) . Goodchild is a more unusual name however and in 1945 Elizabeth M. Goodchild is on the rolls at 45 Sun St (that would be on the other side of the road) and Irene F.Goodchild was at no 10 Sun St. In 1950 Irene F and George J.Goodchild are living at back 18 sun St.
Mike