I'm doing a long point to point race this year that straddles two OS maps. Harvey don't print this race map. I wasn't able to find a satisfactory map commercially.

My solution is to use an OS subscription (only £8 in clubcard vouchers - I'm a Yorkshireman who moved to Scotland) and print maps on to waterproof paper. I know that there are a few options available for A4 sheets. In order to get a 1:50,000 map onto a single sheet, I'll need to print two sides on A3, which I can do with my printer.

The sticking point is that I can't find waterproof paper in A3! Does anyone else have experience with printing maps? Which papers are good in an inkjet printer? Are any available in A3? Do you have any other handy tips?