Yeah, but this isn't any old Grob!
Cruising at 50 000 ft and straight in at 42 miles!
The landing fee would be minimal in the scale of the fun!
"Stansted, Grob overhead Old Buck Flight Level 500 requesting straight in approach"
(Smug reply) "Grob copy your transmission and understand you are at FL 50" (yawn, don't you PPLs understand flght levels?)
"negative Stansted, Fifty thousand feet and heading in, right down the slot!"
50 000 in 42 miles would blow their Boeing / Airbus minds... well worth a couple of million of disposable income!
I would expect applause when I arrive in my NASA pressure suit!
Dreams are made of this.