PWP, understanding about budgets, I'd suggest firstly look at Harry Mendelssohn on
http://www.harrymendelssohn.com/homeframe.html. I have one of their budget HM40 headsets, which are at-least as good as the basic David Clarkes at twice the price, and only very slightly over your budget at £85 (when I bought mine cotton covers and a headset bag came with them, I assume they still do the same).
Second, headsets come up quite often on eBay pilots gear at
http://listings.ebay.co.uk/aw/plisti...783/index.html although no always at bargain prices. If you're buying one from eBay, check it will have the right plug, a lot of the cheaper ones are ex-mil sets which use a different system.
G