I couldn’t find anyone who did 17″ tyres for my A40 pickup when I was looking a couple of years ago. I didn’t want them anyway because the old ones I was replacing rubbed when cornering. Especially cornering on a bumpy road.
So I bought a set of 16″ Somerset wheels from the club and did it that way. Also fitted a Somerset differential. Surprisingly the original Speedo reads spot on according to my satnav. Now done 9000 miles with this arrangement.
Further to my last post. If you have not yet purchased some 17″ tyres you might be interested to see the dramatic difference that I found in the diameter between 16″ and the 17″ tyres that came on my truck. There is a picture here. Also shows where they rubbed.