B&Q half price polycarbonate (greenhouse sheets)B&Q are selling cheap polycarbonate sheats at present
£9.99 for 0.7 x 2.4 x 10mm, double glazed, with £7.50 off when you buy 5 sheets.
This works out cheaper than Screwfix or any online polycarbonate supplier.
I'm changing from glass to polycarb for safety reasons (little kids and glass don't mix well). It's turning out to be easier and cheaper than I expected (not often that happens...)