This is response that I got back from Uber CS :-
In order to perform a pick-up at Manchester Airport, your driver needs to wait in an area to receive a trip request. They then need to pay separately for picking you up from the pick-up point at Manchester Airport. This is done at the
Paid
Multi storey
Car Park and the cost for using this car park is £6.50.
We have added this charge on top of the fare of the trip and it is then passed in full to your driver. Uber does not take any part from that pickup surcharge.
I think what they're saying is that because they now wait in the car park (rather than coming from outside the airport), they are charging the rate for 1 hour - which seems to be £6 from the MAN website. So, it's more convenient because there are generally always cars available, rather than having to wait 5-10 minutes like in the old system.