Ok, thanks IGN. As a comparison I have 295mm at front cross-member and 240mm to bottom of rear dif.
Insurance is fine, I pay a bit more but are allowed a couple of mods. Told them it was lifted, just not how high.
It will only void warranty if Jeep can prove that it was the modification that caused a part to fail, which is often hard to prove. I broke a front drive shaft at the CV a month ago and it was fixed under warranty. The dealer said the lift will cause the CV to wear a bit quicker but it wont cause it to break and Jeep would never be able to prove that it did.
The tyre might be a problem with warranty as according to the "letter of the law" they would be illegal but I only put them on when going 4WD'ing otherwise I run the standard tyres.