My lack of patience got the better of me and whilst pottering about in the garage I thought I'd just take 20 minutes or so out and see what the sanded flashline area polished up like. I've bought some Farecla rubbing compound and beginning with the courser G6 grade then moving onto the finer G3 I spent about 20 minutes working on a small section of the nearside rear quarter. Here's what 20 minutes gets you. I'm quite impressed with the finish. My efforts have shown that there is still some more work to do in this area as you can still faintly make out the flashline and even after 20 minutes work with the rubbing compound theres still quite a lot of faint scratches. You have to look hard but they are there ! The little bits of white you can see are bits of fluff that came off the stockingette I was using to apply the Farecla. It was quite labour intensive as you have to rub quite hard. I'm going to look for an electric polisher to make this job a bit easier which should also help to produce a better finish. I also took the opportunity to try out the hole saw I bought to cut the holes for the rear lights and indicators. It did exactly what it said on the tin and errr... drilled a hole. Perfect ! The only problem now is that if I need to do some more wet sanding on this area, it's all going to end up in the boot. Not a big problem but I was using the boot to store some other parts which will now have to be moved. Still a bit of work needed on the patience then !
UPDATE. Some of the scratches I referred to are a bit deeper than I would have expected given the grade of paper I've been using. This suggested that either the paper was not the greatest quality or I've introduced some dirt or grit somewhere along the line. A bit of research suggests that better grade paper may help so I'm going to get some 3M paper which is supposedly more consistent in the grade of abrasive used and what the professional body shops use.