In reply to samsimpson:
if your looking for a new helmet i'd seriously consider looking at Petzl new offering, the sirrocco.
it looks like a 'foam' helmet that hasnt been finished with the plastic outer, however its a different material and doesn't need the plastic outer. its seriously light, infact the heaviest bit on it is the chin strap buckle!
i saw a destruction demo of it at kendal and its pretty sturdy, the demonstrater stood on it several times and jumped on it. then cut it with a hacksaw and stabbed it with a knife and it only then broke when one of the audience jumped up and down on it quite hard. so pretty strong!
it was also fairly comfortable to try on.
and i hear the price is around the £60 - £65 mark.
well worth a look at!