Original Craven mountings are very difficult to obtain and I generally make my own. As you say the front mounts fit at or near the top of the shock absorbers. For the rear mounts I use (or make) 3/4 inch diameter P-Clips and fit them around the rear mudguard support stays.
If you are only using a Rack and Top Box I don't think you will need the extra supports that go down to the rear footrests. These, of course, would be required with Pannier Boxes if you intend carrying a lot of weight.
Ok, I've left myself wide open to criticism on the last comment but I do write with over 45 years of experience, having used these bikes for serious long distance touring and camping holidays since I was a teenager, and still do.
Get yourself a rack and topbox fitted for now and if you feel the need for panniers in the future you can always modify your mounts to suit.
BTW, I'm looking for a set of 4 Straight Craven Pins (not the 90 degree angled ones) that attach to the rack and go up inside the Rubber Bobbins on the back of the Pannier Boxes. If you come across any, or indeed if anybody reading this has some spares, I would appreciate the opportunity of buying them.
Beezageezauk.