Got these pannier frames with the WWS LTD stamped on the fold outs,I call these the BSA type,it could be the company that made the complete pannier or just supplied the fold outs,probably one of the many metal pressings companys that supplied parts for the war effort,it could be on other items made by the same company.
below,these post war Triumph pannier frames still have their original labels,says the maker is Triumph, its possible that some were made in house and others out sourced to other manufacturers.