After my recent laning trip I want to fit slightly bigger tyres to my d1as I dented the rim as a result of a small sidewall.
Plan to replace current 235/70/16 with either
235/85/16 or 265/70/16

Anyway to do this I need a lift. Cheaper the better so are there any issues with £40 lift blocks? Or I could try and get used springs and shocks for £80

Save your money, I run 235/85 16 Cooper STT on a D1 with standard suspension, only thing I did was adjust the lock stops to stop the tyres fouling the radius arms.

I prefer a narrow tyre to cut through greasy top layers to more tractive ground, wide tyres offer good floatation but this can be achieved by dropping tyre pressures to 14psi if you really need the floatation, just re-inflate them once you're through the worst bits, you should get a decent compressor as a matter of course, it'll pay you back over the years.

You'll still get an extra inch and a half under the diff with 235/85 16s, the taller the tyres the more diff clearance you get, but every modification, even changing tyre sizes, over standard means compromises and costs.

In my siggy is a link to my old blog from my Disco build, look in there for the wheels and tyres post, the new wheels and tyres are the Coopers, the side by side comparison is startling.