hi - always satisfying to have a result. I've not seen or heard of this one as a Wedgwood mark, and would be useful for the Board's archive if we had perhaps a commencement date to link with the mark, and if it was applied to a limited range of their products, or if it was used generally.
Approximate dates are known for other related backstamps for Wedgwood - the early trade mark for King's Lynn Glass and the later Portland Vase for Wedgwood - plus the variations on the use of the Company name etc., and the very early RS-W for Stennett-Willson.
For whatever reason - health & safety or simply practical issues - it seems that Wedgwood used sandblasting only to create their backstamp, as opposed to acid like most other manufacturers. Most of the time it's possible to see the difference between the two methods of marking, which can be a pointer to an id.
Perhaps your friend can point us to a book, or particular piece from Wedgwood and would be really good to have a date - thanks