ORS 4 No. 974. (CAA website)
The one that I and a few others campaigned for. Basically as long as you've previously been issued an EASA IR (Incl the UK) and presently hold an ICAO one you're exempt.
In fact even if you let your ICAO IR lapse by more than 7 years the only thing you have to do to regain your EASA IR is an assessment and required retraining with an ATO prior to retest.
C.