This item of silver plate’s makers seem to have decided to put every historic UK silver mark and a few others which are not, on his candle wick trimmer plate.
Some of these marks, including the lion’s head erased, this forum has been asked about before:
Now we have a set of initials, probably LS or IS/JS or even TS.
This is almost certainly US plate which frequently used faux UK marks and presumably there are limited numbers of US makers with the same initials.
CRWW