Surrey Highways are planning extensive road works on the A24 by Downsend School. This is to solve the persistent flooding problems in that area. The sign says start date 3rd February and delays are "possible" for 3 weeks. That's possibly the world's greatest understatement!! There are already extensive delays without road works!
The only alternative route is to take Barnett Wood Lane where at busy times (and when aren't there!) there are existing extensive delays due to the ongoing gas main works. So that's the only two ways out of Ashtead going west controlled by traffic lights and restricted traffic flow. What excellent planning! Good luck!