help ID-ing large piece of Sheffield plate

The family “turkey tray” got its annual run-out and for the first time I looked a bit more closely, having recently succesfully researched a set of sterling teaspoons on a site - and read on a bit further on plate.

The item is an oval salver, 18" x 14", weighing just under 1.5kg, with gadrooned edges (as I believe the “rope” style is called?) and engraved lions on either of the long upper borders in rectangular inserts that are clearly deeper (purer too?) silver. There is a little copper showing through in places, mainly the inner rim. My reading would make this a very good fir for a “Regency” piece - c1800-1820 or thereabouts?

Apart from the engraved lions the only other marks are on the rear rim - one is a pair of punched stars separated by a punched dot, the other a very small capital “H”. I have decent photos of the front, back, engaving and marks - but any one of them is too big to attach here it seems. Maybe if anyone has knowledge in this area about possible maker and whether my conclusions might be about right I could email attachments separately?