Small cogs

Probably by breaking another Whippet for spares, there are plenty around,  I have scrapped many as no demand.

If no donor Mower's with good sprockets are available, Pilot Bore Sprockets are available at all reputable bearing suppliers, who would also advise you on the pitch of your 7 toothed sprocket if not known.

Naturally once purchased an Engineering company would need to machine out the bore to the "D" profile.

This is how I go about this problem as a solution to a worn sprocket, but donor mower parts are certainly the cheaper and most  hassle-free option; and Original OEM British made quality.

Thank you both