Pox. Too late. Next time, maybe...
Anyway, running out of spare time to get this donw, In desperation I used Crystal Clean in Merchant's Quay (there's another branch in Q-Park, Grand Parade).
The polishing had visible wax swirls, and there were several other marks which were not polished out before the top-coat was done. They did re-buff the swirled paint, but only after I asked. Inside, it was okay, but they also put slippery interior polish on the pedals (???) making them quite dangerous to use, and they left the floor mats soaking wet.
Despite the amount of product used on them, the seat leather had dirty "water" marks on it that I was able to easily remove with a damp cloth later. (They might have saved me this job?)
They also didn't really clean the wheels (I've the annoying-to-clean 15-spoke alloys), but I wasn't too pushed about the wheels anyway.
Discounted down to €100, plus my €5 parking. An expensive lesson learned.