bpoole- spreadex will quote anything over £7m market cap.
GTL they do on i think (didn't check if i'm honest, they have plenty of my cash to cover open bets at the moment) 20% NTR (margin); if they have never quoted on a stock before and they generate a price for you (which takes 10-5 mins or so) but may charge 30% NTR.
I've never seen a list of all the stocks they quote- but you can see if they do a stock by clicking on 'financial'; 'all markets'; 'equities'; 'uk shares'; then select the first letter of the stock you are looking for.
cojones- spot on, they are the main reasons for GTL's decline in price (and lack of a rise as we approach production). Putting all your savings into one stock was rather foolhardy- but hey its your money ;-).
Best of luck, I only have a few here as I think they are undervalued and that present corn prices are very high, oil prices a little low; I'll add more as the price drops and probably add a few on news of production in Jan/Feb/Mar or whenever it is- to be honest a few months here or there doesn't concern me.