Hi all (again ! )

Think i've read hunderds of threads and replies regarding tyre choice but i'm still no further forward so need help again !
Basically....Defender 90 200Tdi 2" lift kit. Pay and play days on local site (Broxhead in Hampshire, very sandy/mud/water/ and silty ) greenlanes and some trials.
Hardly any road use....

What tyres and more importand what size can I put on without shreading diffs etc ? I like Big but as I keep getting told, I know size ain't everything

Thanks everyone.

You want a decision made for you? - get some BFG MT 265/75s