UKH

I grabbed a cheap Crux AK47 a few years ago but have since pocked a crampon through the Kevlar/vinyl material.

I'd normal repair packs with seam grip, but am unsure if it would work on this material. Can anyone recommend a product or method that will be strong and long lasting?

Cheers

I would put a few stitches in it then slather on something like seam grip, probably on both sides. Putting a patch of say Gorilla Tape, inside and out again, also would work reasonably well for protecting the stitching.

A patch of similar weight fabric on the inside sewn around the edge, then sew over the tear back and forth to stop it catching on anything.

If you don't have a sewing machine capable there are plenty of places around that'd patch it up for a small fee. Crux themselves recommend: http://www.lancashiresportsrepairs.co.uk/

Other than that Alpkit have places in the Peak and Lakes and are easy to call in.