Most Instrument training will be done on EASA aircraft and an IMC Rating is not valid for these.
Not sure where you're getting that from. An IMC or IR(R) rating is perfectly valid in the UK on EASA aircaft, just not valid outside the UK.
My SPA-ME-IR is perhaps 3 years out of date, and no longer properly endorsed on my EASA ATPL, as it had expired when I applied, so is just listed as a previous rating. Therefore, either way the paperwork needs to go to the CAA. Will discuss it with the examiner and see what comes up.
Thanks for all the advice.