Unless it's S for Shipmans which was the shop next door originally to Schofields so the location would be right. Just had a dig around as I thought I had read about a connection and Shipman was a colleague of Schofields and persuaded him to buy the shop opposite himJust a thought
Don't think it is Shipman's. If you search for Lands Lane/Headrow on Leodis, on page 2 you can see this shop went through at least three changes of use in the 30's and 40's. Shipman's appears on the other side of lands lane, next to Schofields but was bulldozed to make way for Schofields.
Could be totally wrong but I was under the impression that was a leftover from a previous incarnation as a horrible clothes shop? It was definitely at least two or three ladies shops before it was Carphone Warehouse.Always thought the design of that glass looked quite modern...I would be really interested to find out though!