You can forget about doing the IR(R) revalidation, as the IPC allows you to then go to the CAA and pay them for issuing an IR(R). They will issue an IR(R) based on passing a third party foreign IR skills test, or proficiency check. It doesn't work the other way round, so you can't do an IR(R) revalidation with an EASA FE, then get the same rights as having done an IPC. You would think that a current CFII who is also an EASA FE in the European theatre should know that, and suggest that option.
So it's just the CFII you need to find, and there are a few of us about. If you're in Northern UK, PM me, if not, keep looking.
Some are reasonable, charging circa £30/flying-hour (myself), there's even a guy down Cambridge way who doesn't charge, and others probably cost a bit more - especially EASA FEs, I would imagine. There are even a few jokers who want £325 day rates and suchlike.