PC London Commuter - Train Won't Move Once Taking Over A New Service

I've come across an issue in timetable mode for London Commuter where once I finish driving a service and accept to drive a new one, the train won't move once the cab is set up, doors closed and cleared for departure.

I thought it may be a one off issue, but I completed a different service and then went to drive another and nope, still no movement

Anyone else having this issue or is there something I'm missing?

 

Update: Waiting until less than 2 mins before departure before accepting the service seems to have worked.