Hi Ben,
From what I've seen on various forums over the past few years it really can depend on the individual car. The only tyre sizes you can 'guarantee' to fit are the OEM ones 235/70R16 and 225/75R16. That said, MOST people will be OK on 245/70 or 245/75 with no problems and SOME have managed 235/85R16.
Of course, thats all with a completely standard car. If you cut the rear arches and trim the front bumper then the 235/85's won't be a problem and will give you the best clearance under the diffs. One thing to remember is that 235/85 will make your gearing taller, so you may struggle a bit with acceleration in higher gears and motorway hills might need a change down to 4th (assuming you have a Tdi).
If you stick a suspension lift on then you have even more options. Take a look at my Disco in
THIS LINK. I have lifted mine with Britpart springs supposed to give 1" to 1-1/2" of lift. My actual lift from wheel centre to arch lip was about 2-1/4" to 2-1/2". I suppose the old setup was tired? I have now got 265/75R16 muds on with no problems apart from loosing steering lock. My rear arches are trimmed just on the inner lip, not a proper camel cut, but the aim is to eventually open up the arches to the first crease and fit TD5 arches.
I suppose my choice (if I did it again for least hassle) would be 245/75's. They should be a nice compromise between bigger for better looks, better clearance under the diffs and not too expensive, whilst not overgearing it too much and creating problems with steering lock and arch clearance.
Hope that helps,
Steve.
