It isn't in the middle of a panel, it is on the corner edge of the boot area (see attached).
There are numerous other little scratches on it that have been treated so will not deteriorate any more, but this one hasn't. Numerous Youtube videos have been watched, and I'm now armed with the local decent paint shop's contact details. I have all the gubbins required other than the paint, so will look into taking an extended lunch break sometime mid-week and making progress there.
I could get them to do it, or I could get them to mix up the paint. The former means it'll be done right first time, the latter means I can fix all the little scratches myself. Food for thought, but that's as far as I can go this weekend. Many thanks for the input so far, gents.