Hi Royston,
We use this site farily frequently, as my brother and family live in Reigate. It is a very pleasant site, well cared for up to the usual high Caravan Club standard. There are some good local walks in the surrounding countryside. It is worth driving a few miles to Farthing Downs for walks and views.
As regards the access, as Cobbers has said, you must approach from Shepherds Hill (B2031), from the A23, as the lower half of Deans Lane is too narrow for safety for either caravans or motorhomes.
The CC directions take you off the M25 at Junction 8 and then down a road called Gatton Bottom to join the A23 just north of Merstham. This is OK; Gatton Bottom is wide enough for 2 -way, but a bit tight if you meet a truck or speeding white van.
There is an alternative. Leave the M25 at the M23 intersection (Junction 7) and go north up the M23 towards Croydon. The M23 shortly runs out and you join the A23. Continue under a bridge, where it narrows to one lane northbound and in about 200yds turn right as if you are going into the lower end of Deans Lane, but actually do a U turn - there is space to do this using the exit from Deans Lane. It is a common manoeuvre there, so beware of others doing a straight U turn on the carriageway without using the exit of Deans Lane. Now proceed southbound on the A23, keeping right as the southbound M23 exits left. After about 0.5 miles, turn left into B2031 up Shepherds Hill to acces the site from the top of Deans Lane.
It sounds complicated, but it works!
Cheers
Paul