The opening post does say "tarmac rallies" so I nominate Longcross near Chobham where the tarmac surfaced 'tank testing' inclines were often used on special stages.
The inclines were 1 in 3 and 1 in 4 , I seem to recall, and you could get a great deal of 'air' if you were daft enough...
If you did this with enough enthusiasm the resulting flat landing was likely to push the front struts up through the bonnet so it wasn't an ideal approach to take!
They were very popular viewing points, as you can imagine
The same stages also included the low-banked oval track that's been so popular with motoring magazines for photo shoots and the 'snake' with it's fairly impressive climbs and drops, which has been used in many feature films including the fairly recent CHILDREN OF MEN and Francois Truffaut's FARENHEIT 451 back in the 60s....as well as GEORGE AND MILDRED in the 80s....
Last I heard the place was being sold off and 'developed'

does anyone have an update on this?