A bit of a long shot but has anyone got an idea how much a piece of 65x120cm 4mm thick toughened glass is likely to cost?

theres lots on ebay

http://shop.ebay.co.uk/?_from=R40&_trksid=p3907.m570.l1313&_nkw=Toughened+Glass&_sacat=See-All-Categories

Hi Bud
You would be looking at £40-£60 Try Solaglass trade . Maybe cheaper with Laminated
From a Friendly Glazier

Yup £40 to £60 quid depending on where you live - dearer in London if you are in a hurry

Thanks guys. Always amazes me how quickly a query gets sorted.