With regards to the suggestion that Luton Airport pay Ryanair:
We have to remember that Ryanair were at LTN before STN. The move across to STN came about because of LTN charges and check in facilities.
Now there are 40+ airframes at STN and only 4 at LTN.
I expect that the LTN management would be keen to work out a deal to get back some of the business they have lost to STN.