777mm is correct .....
Suspension height on my ride is as follows....
"Measured from the centre of the mag wheel to the top of the wheel arch"
(Passenger side) FRONT = 460mm .... REAR = 490mm
I have the original front bottom skirt fairing and the 265/70x16 clears the edge of the fairing by 15mm. The 265 also fits in the wheel arch area with no need for cutting or "Tubbing" ... The 265 sits / fits nicely on the original LR mag.
I would luv to fit the 295 wide tyre ... But would have to tub the wheel arches + mod the rear doors (and buy the 8+" rims)
I see that you do not have the front bottom fairing fitted, so I recon you could "jerrrrrrst" fit the 265/70x17's ... (but you would need to articulate the suspension to ensure nothing catches / touches)
Go to Ian Diffen in Collier road Morley, (Green building Between Toyota and Missus Macs Pie factory) ask for Peter ... mention another "RRC fanatic" and he will cheerfully accommodate a prefit (I do it to them every time) and tell em "No rattle Gun" for nut tightening :)

