I talked to Mark Leddington about this very issue earlier in the year.
You are right. No real interest in filling the orders.
Production is at capacity, without adding an extra shift to extend the working day they cannot make more...and to do this would require a major change to the organisation of the production side of the business. Also, it would need a new team of craftsmen to do the work. They have enough trouble training/finding people to replace retirees and leavers.
So there is no realistic way they can go from 750 cars to 1000.
And apparently no real interest in improving production techniques. If the body tubs were properly jigged and finished to a standard practically all other parts would be off-the-shelf, pre-made, pre-drilled and ready to fit with a minimum of adjustment. This would have the advantage of interchangeability in the case that new mudguards, cowls, or bonnets were required. As it is too much customisation is required for every car.