Can someone tell me what material these are made of and how warm they are likely to be? I can get a 'friedly' one, with VAT & postage, for £38. That puts into a different league for me so it needs to be looked at a different way. Do you reckon the jersey is warm enough for a cusp season (i.e. early spring, autumn) outer layer? Is there any warmth or windproofing to it?