About fifteen years ago I bought an Amex topper with a trailing wheel and which is really good for clearing old pasture up to about 5 feet hight. (I have cleared fields of scrub higher than I was seater on the Dexta tractor) It needs a pto to drive it which you could from a tractor but not a Range Rover.
It has shear pin and mine is 6.6"' cut. I think they do wider models and would recommend you have a look at them. However, bear in mind I am more of a smallholder at 60 acreas, that most of the guys on the forum.
I got it from a company I think around Kidderminster somewhere. If you email me I will dig out the old invoice.