No keeper plate on the outside?
Be very sure about the thread before you work with a puller. 8M is a far more typical size than M7 for anything, Use the wrong bolt and that alloy speocket will shed it's threads in a second.
I don't think I have anything here that is M7 and I have bikes and cars in metric only!
I have a Bob Newby front sprocket, no you don't have that, or a Norman White one which I also have. Newby uses M8, Norman I can't remember, but I think 5/16".
Steve Maney doesn't use that belt form, I'm guessing RGM or Norvil. But someone must recognise it.
A standard Andover Norton front sprocket puller works fine with the 5/16" bolts substituted with M8. Don't use any other method, or you will have a mess on your hands.
My puller has been slotted to make it more universal, not difficult to do.