You dont need to go as aggressive as Mek, acetone works fine and is recommended. You also use the acetone as preparation for gluing. Make sure you use a good 2 part glue, not the temporary Bostic type stuff.
You can get the acetone in small bottles from a chemist, or in larger quantities from ebay.
Dunno, the blurb says 'for softening old glue to remove patches etc'...
I have used this very MEK to remove a snap davit pad from my dingy. It works, but (depending I guess on the old glue - mine was in good condition, but I needed the pad off) it can be a b**ch. I found using a brush and wooden spatula works best - wet the edge and prise with the spatula. It takes an awful lot of work though... Constant reapplication and teasing required.
I took the broken transom out of our knockoff Zapcat using a heat gun. On half power, and keeping it moving so as not to scorch anything, it just turned the glue to liquid without harming the fabric. A thin flexible paint scraper helped to peel the layers apart.
Try white spirit, it seems to break down synthetic rubber type adhesives quite gently and not cause any damage. It may not work on MEK or acetone based adhesives however.