Hi Gina
Welcome to the forum, As far as I know Henry's stores started in the mid 30's at 59-60-61 High Street then I can only assume because of wartime bombing and being bombed out they moved to 23 Martineau Street. They then had new premises built on the corner of High Street and Martineau Street at numbers 52 -53 High Street these premises were closed in 1958 and yes they were to the right of Union Street which is as you will know where Henry's Stores moved to in c1958 and ended their days.
Please do not accept this as gospel as I have made a couple of assumptions, so if I were you I would check everything out again, though the addresses I think will be correct as they come from Trade Directories. I hope this has been of some help.