Plastic Sheet / Polytunnel Covering (Bellevue EH7)

I'd like to find some clear, thick plastic sheeting for use in a garden as covering for a very small polytunnel/greenhouse. It's about 2m sq. at the base and 2m high. If anyone has the end of a roll, or some that's been used and is in a reasonable condition - I think that might be plenty to finish off the project. Many thanks in advance if you may be able to offer.