Thanks for the advice. I've now had the opportunity to try a 'technical base layer' and found that it actually works quite well. Certainly an improvement on the old heavy cotton T shirt. Now that I've clocked nearly 1000 miles on my 'cheapie' first recumbent I am now looking at an HP Velotechnik Street Machine which has a radical seat design and the option of a mesh seat. I think that'll be my next step. Thanks again for the replies and advice.