Thanks to both...
I printed and cut it out, stamped the holes out with a 7mm hollow punch, then lay it on the sump. It seems to be a perfect reproduction. I make them by laying the sump (or a gasket if it's in usable enough condition) on my scanner. Then I "trace" the gasket using a graphic drawing program.
I haven't put the motor back together yet, because the last couple of days I've been trying to replace what I believe is called a "skirt" - ie. a circular section of metal strip that fits just behind the front axle. I assume it's there to keep the grass circulating until it's thrown backwards into the catcher - and - to protect the front axle bushes from damage while mowing.) Realised it was missing when I noticed two large pop rivet holes either side of the deck, with nothing attached.
Anyway, I guess I'd better poke one of the bolts through the holes first, to check it's as good a copy as I first thought.
