Andy, I don't think you have Meguiar's M105 in the UK quite yet, but I know you have Ultimate Compound which is derived from the same abrasives technology. Halford's should stock it as should Autopitstop and Elliot's Car Accessories, among others. (Yes, I cheated and used the Stockist Locator at Meguiar's UK - Car Care Products )

I would suggest you wash and dry the car, clay it, then go over it with your G220 and a foam polishing pad with the Ultimate Compound. Don't be afraid to run the machine at speed 5 and use a good bit of pressure on the pad. I always recommend putting down enough pressure to stop the pad from spinning, then back off just enough to start it spinning again. Work in a small area, roughly 60cm square and overlap your passes by about 50%. Move that machine very slowly over the paint - take your time. The Ultimate Compound will stay wet for a very long time so in that 60cm x 60cm area you should be able to go back and forth, then up and down, then again back & forth and up & down. Wipe off the excess product before it dries and move on to the next area. It's always a good idea to do a test spot on the bonnet first, then pull the car out into direct sunlight for a critical evaluation. If you need to give it a second pass, do it. If a second pass still doesn't give the results you're after, I would try a foam cutting pad in a second test spot. A foam cutting pad on a machine like the G220 can at times leave a bit of haziness in the paint, although in so doing it can also more effectively remove severe defects from hard paint. If this haziness occurs then you'll need to follow up with a second pass using the polishing pad as a step down to finish. Hopefully a couple passes with the polishing pad will do the job and you can skip the cutting pad altogether.

After that you can go straight to a wax or, for a little extra pop, hit it with a pure polish or glaze before waxing. Just don't use a cleaner wax if you opt for the pure polish/glaze step - it will remove the polish/glaze!

That ought to get you started.

Cheers!