Pluto, I have just remembered Chris Watson had an Airfix toy shop before he moved into Dunphy's.
That was were Posh Frocks is today and has since been occupied by Ainsworths as a butchers shop and also Cafe Maderia.
Chris Watson had his toy/Airfix shop on the corner of Victoria St/Queen's Road, there is/was an antique shop there recently. He then went to Dunphy's where his father worked and took over when he retired. Can't remember the exact timescale but I think they were both there at the same time as some point.
As for the Posh Frocks shop, I remember it being run by the Ruscoe's as a sweet shop. Stephen's mother and brother owned/ran it. Can't quite remember if Chris had a toy shop there though??
Ainsworth was originally in Owen & Son butchers, next to the 'Zion Passage' (that never had a name in my day!!) Then, as you say, opened his own butchers where Posh Frocks is now.