I don’t see any reason why the order couldn’t be revised, if it’s a factory order and the dealer can/will do it. TBH, in your shoes I would consider upgrading the model if you can’t get it on your original choice. You mention that you would prefer the larger screen anyway so the £200 you mentioned for that, plus all of the connected nav benefits doesn’t sound too bad. It works out around £1.28 a week over a 3 year lease.