In reply to Stuart Wildman:
The patching kit that came with my Exped mat seems pretty good. As I recall it recommends applying a layer of the glue, waiting for it to cure, applying another layer, waiting again, applying a third and then topping off with the patch.
For those with less time on hand it allowed for one layer and then the patch, with the caveat that this is likely less of a permanent fix - but it seems to be holding out for my punctures Thermarest.
Possibly all academic, though, since I'm not sure what glue/fixative it was.