Advice please - Omega 198.030 f300 caseback gasket

I have just replaced the battery on this 198.030 cal 1250 and that is fine but I need a new caseback gasket and when I look at various sites, whilst some refer to the caseback number (and I haven’t yet seen one for a 198.030) others refer to the part number.

I appreciate that I will probably need to get a generic gasket but if anyone can recommend a part number and/or source (ideally but not essentially in the U.K. because of postage charges) I’d be very grateful.

Looks like a perfect fit. Many thanks

And ordered. I’ll let you know how I get on. Thanks again

Just a shout out to @ketiljo for sourcing the caseback gasket, which I’ve now fitted and feeling pleased with myself.