I need to drive to Dorking this Wed morning and be there by 10am. I'll be leaving from east London (E1) and will be taking the southbound Blackwall tunnel / A2 / M25 west route. Does anyone travel this route by car on a regular enough basis to have an idea how bad the traffic will be, and how long it might take during rush hour?

I'm currently thinking of leaving around 7.30am so giving myself 2.5 hours to get there (without traffic it should take 1.5 hours). My biggest concerns are the snarl up around the Blackwall tunnel entrance and the M25 - I should be going against most of the traffic on the A2 so thinking that should be alright.

Really appreciate your input so thanks in advance!