The Guildford via Cobham both have a lot of slack in the country stations as well as London stations, take this for example:
Real-time train running information for 1334 departure from Guildford to London Waterloo on 03/09/2024. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk
At stations such as Effingham Junction, Cobham, Oxshott, there's 1 min of dwell time, which is more than sufficient (As a comparison, Clapham Junction also has 1 min dwell time). The Surbiton to Wimbledon section is pathed at 9 min, yet the train in RTT above did it in 6 mins.