For those who are interested, this is the response I have had from the supplier whose website is quoted above - compressed height:11.5cms (and, incidentally, maximum height:34cms). My Plus 4 clearance at the front jacking point is 14cms. At the rear the jacking point is the junction of the cross/side members. Here the clearance is 10cms, but aft of the junction (on the side member only) the clearance is 13cms.
As for the Skoda, there is plenty of room. Their compatibility check function must lose them a lot of sales
