AT Tyres for my Disco 2

Hi
I am looking at putting some all-terrain tyres on my disco 2, I am running 16" wheels and in my hand book it states I should use 255 65 16 with load and speed ratings of 109 and H.

From looking at AT tyres, either BF Goodrich or Grabbers they are only S speed rating. I also want to run narrower tyres for more grip eg. 235 70 16. Am I going to get into trouble with insurance / law if I have different spec tyres on vehicle to what manual states I should use????

Also anyone tried any of the new Grabber ATs?

Thanks

I think as long as they are legal should be ok, if wrong i will be corrected changed the tyres on the freelander to a slightly narrower tyre and was ok

We've got General Grabber AT2s on our 2a they are 235/85/16's and perform well on and off road.