Thanks for all the info chaps - it's very much appreciated.
It looks like the 195/65 option is the one to go for then, as it's going to give me the extra ground clearance I'm after at a reasonable price, and for an old miserly Morganeer cheapskate like me that counts for a lot!
The 195/70 tyre seems to be for vans, and the 185/70 tyres (CR6ZZ) are no doubt super, but to my mind are silly money and I couldn't justify spending £230 a corner when for the vast majority of time I'm just pootling about with the good lady Christine keeping a watchful eye on the speedo.
Thanks again.