Royal Mail have history with wasting money on EVs. When I was there our Malvern depot was issued with 6 EHCT's. Electric High Capacity Trollies. These cost c. £6k each. 6 months later, only 2 were working. They short circuited in wet weather, sometimes driving themselves. Into a shop window on one occasion!
They also would run out of charge on the hilly routes. For H&S reasons (our vans did not have a tail lift) we were not allowed to recover them ourselves if they broke down. Once 'my' EHCT was left in a car park for over a week & only recovered when the Plod found some gentlemen from the 'travelling community' trying to push it to the local scrappy to trade in the batteries.
When I did some research I found out the model RM had decided to buy was designed for work in warehouses & hangers - usually dry & flat environments.