British silver with confusing marks

Hi all, newbie here. I am trying to help friends identify a set of sugar tongs that they bought in Belgium some years ago.

So far, I can see that it is by Joseph Gilbert of Birmingham, and that the capital I indicates sterling. I have also seen the back-to-back Cs (like the Chanel logo) and single key but don’t what they indicate.

What really puzzles me is the A enclosed in a circle, which seems to match up best with a Dutch mark from 1835.

Any help greatly appreciated!

This is not a hallmark as the tongs are electroplated. JG is either Joseph Gilbert or John Gilbert of Birmingham. If the tongs were English silver the indicator of silver would be the lion passant mark. I suspect that the capital I is actually the number 1 which, in combination with the A, gives the plating quality, A1.