DD:
I'm guessing it's a game gun (rather than a fowler or pigeon gun), albeit a more heavily-built game-gun than some. Check the proofs, if it is only 1 1/8 oz, that's the lighter British proof. If it is stamped 1 1/4 oz, that's better but still not necessarily good.

Look at the lumps. Are they large or small? Some W&S game-guns had very dainty lumps, and common sense would dictate they not be subjected to anything more than their original proof.

I'm also guessing there is no third bite. That would kiss it off for me.

I posted this pic a long time ago: it shows a Greener 'Empire' duck-gun compared with a Hellis game-gun. Both were proved for 1 1/4-oz loads, BTW. Check the difference in length of the action bar, as well as the difference in length and thickness of the lumps. The Greener 'Empire' also has a cross-bolt 3rd fastener, and as such qualifies as a candidate for DR conversion, to 'N-for-B' cartridges and loads only, with care! The other gun is not even in the race. This is my opinion only, and I hope it is clear: I don't want to rain on anyone's parade, but I don't want to see anyone get hurt either!