After taking the Coupe out of storage (posh term for the garage) I put a full bottle of petrol improver in and topped it with 99RON. It did do the engine light the first trip but I reset this and then gave it a good back road open throttle session to heat it through (30+miles) and it has been fine since.
https://smile.amazon.co.uk/gp/product/B01N5QILP0/I did choose this specific one as the mouth of the filler is pushed back into the pillar and so the long thin neck allows me to avoid spilling it. It needs to be long enough to push the filler flap in.
