Hi Guys - first of all many thanks for your comments - really appreciated.
OK, in no particular order...
We live in Manchester and whilst we are near the countryside we'd have to drive on a road to get there - we have no access to farmland. I guess we would do no more than 200-300 miles on road each year.
We reckon our first port of call is to investigate the CVRT family more thoroughly. With that in mind, we have contacted the Alvis Fighting Vehicle Society so we can check out the CVRT and see what we reckon - any suggestions, comments or alternatives would be hugely appreciated, we're totally open minded.
Assuming we go down the CVRT route, what kind of maintenance and maintenance costs per year would we be looking at please? Also, what is the cost of a replacement track - and more generally, are spares available at a sensible cost? And, if so, who from please?
Thanks once again for all the input.