What size tyres

Hi,
I am new to all this , just brought myself a disco mk1 and what to replace the tyres it's on 16 inch alloys I would like to go off road now and then what is the biggest I can put on standard suspension?

Depends on the width of the alloys, but certainly 235/85 R16 are OK on standard 16" rims if you want ground clearance, or is tyre width more important? To go really big you'll need a lift plus arch modification in order to stop the wheels fouling on full lock/articulation.

The alloys are of a Es fitted with 235/70/16 but someone said that 245/75/16
would fit? then if so I could fit BF Goodridge mt or Cooper stt ? does anyone know if this is correct as I don't want to muck up the gear ratio to much.

I would also like some advise on this topic! My 95 Discovery 300tdi has currently got the original 205/r16 wheels on it, and I want to replace them. Is is possible to just stick 235/r16's on? Or do I have to buy myself some wheel spacers first?
Also, where could I get some decent door decals? The bottom of my door is a bit rusty (as you would expect) and I figured a door decal is the cheap way of covering it up!!