If it’s not for you mate would you not consider driving something else? Like doing the old dear journeys to the coast etc?
When driving, don’t ever let anyone bully you with a tight timeframe mate. Your the one driving and it’s your license on the line. You decide the speed you go, not some jumped up planner in the office. If they wanted to discipline you for driving slow, get the union in. There is no way that you can be bollocked for driving in a manner you deam safe, especially when carrying members of the public. If they keep on at you over it, tell them your going to VOSA and the transport commisioner