Thanks, both. I'm very much on a budget at the moment, (having just become unemployed - loads of time, but no money
), so the flysheet conversion sounds a good idea. Years ago, I had a Bukta Linnet tent to which I added a small front addition with windows. They also made an extended flysheet similar to what you've described. I'm going to visit Taunton Leisure, our local decent camp shop, next week and see if they've got an old flysheet and poles. I'll also put an ad on freecycle. I'm not able to get away for a few weeks yet, so no panic. The idea for the extension is really for when I can persuade SWMBO to come with me
Thanks to all for your help.
Nigel