Thinking changing to this size from 255 55 20 Pirelli Verde all weather purely because of planning a bit of off-loading (legal) fun, my other option would be to go for GG AT3 in the same size. Any help appreciated.

AT3s will get you most places in this country. I'm on my 2nd set now and find them to be a great all round tyre. Plenty enough grip for "hustling" both dry and in the rain, excellent in the snow, absolutely fine for the green lanes around me and so far haven't let me down in muddy fields.

I've been running GG AT3s for over a year and very pleased. Decent on road handling and good in all but the slipperiest mud. Mine are 275/40 r20 (V speed rating) There is no replacement for displacement - W O Bentley

MY2013 5.0 Supercharged HSE L320

You could just buy these bargains! Even the correct wheel for your car!

https://www.rrsport.co.uk/forum/topic58066.html 2003 BMW M5 - 5 Litres of V8 Optimax Slurping Goodness in Carbon Black

2013 SDV6 HSE Black Edition- Orkney Grey with Ebony & Ivory. LR Facelift RAI, Genuine G4 Expedition Rack, 4x Warn SBD-160 Spotlights, Warn 9.5XPS Winch, Mantec Underbody Protection and Sump Guard, Full Easy Lift Suspension Module, LR Light Guards, Light Force HTX230 Hybrid spotlights, 18” Compomotive PD1881 on 265/65/18 BF Goodrich KO2, ARB fridge, TuffTrek awning 😎

Hi there, I'm still working out how to do it ?, it's Andy from Chesterfield.

I'm running 275 55 20 Hankook Dynapro AT2, not done many miles on or off road yet but so far I'm impressed. My last truck (Shogun Sport) had Maxxis Bighorn muds on it and the RRS has made it everywhere that went so far