Does anyone now when Walter Thornhill & Co., 144 New Bond Street, London. Retailer - Cutler, Silversmiths, Bagmakers, & c., Established 1734. closed down?
Googling brings up lots of pieces attributed to him as the maker,

there is also some glass, including mostly superb examples, in his 1894 catalogue that states that some are registered designs and also some with suggestions of items being Thornhill design but often in that ambiguous manner which leaves you wondering!
Clearly a retailer that liked his name on things but just as clearly not the maker that some auction listings would have you believe. What Thornhill items are in dealer stocks, they correctly ID as a retailer, are serious money.