I use TL to list my items and if I put in a reserve of under £50 it comes up with an error and that the reserve needs to be at least £50.
Is it different if you list on ebay directly? I think you should be able to have whatever reserve you want. I like to start all my auctions at 99p because it attracts more bidders so I don't really want to start it at a higher amount.
It's just one of those little things that has been bugginh me recently and I wondered if there was a way round it!!