I have managed to talk to an instrument rating examiner, I know I am outside the 36 month window for exams, but surprisingly you get a credit for holding a CPL even after 20 years on taking the CBIR exams , so 4 required of the usual 7. So back to the books again.
Credit is given for IRR flying so only 10 hours at ATO to do a couple of test routes before test. But training outside ATO counts as long as it’s with an IRI who holds an IR.
Be costly at £300 ph for SE IR training. Buts that’s the UK for you.