I agree with jp, it's production wear by the company, and not a Keith Murray design.
Pieces of Brierley that are by Murray are marked with a fleur de lys, the Royal Brierley mark in block letters and a facsimilie Keith Murray signature..........or else they're not marked at all. Frankly, there are far more unmarked pieces than fully marked items that turn up.
Pieces that turn up with either the script mark or the block letters on there own are production wear.
Nigel