Thanks guys!
I suppose I was reading a bit too much, and then forgetting the basics!! It's all very fine to have the moisture, and the heat to kick off some lifting, but I was forgetting the unstableness bit. After all, if the lifting starts, it needs to be able to continue to form a TS.
Thanks very much redsnail, for your tips on predicting them without forecasts. While I'd never fly without checking forecasts (and we're luckey enough to be able to speak to a forecaster over her for just €1.50 per min) I want to be able to develop my own understanding to the point that I can make reasonable predictions from what I can see myself when I look out! So your visual clues are very helpful.
Thanks guys for clearing this up for me, even if it was a bit of a silly question.
dp