It's not the EURO! The IOM and Britain is very , very expensive. Fuel per Litre: Germany 1,04 Euro , Belgium 1,00 EURO IOM 1,28 EURO!!!! I staied last year in summer 3 weeks with a camper on the IOM and the prices was as high as this years TT. The greatest cost for me as a German are the ferries!!!
And I think , this year there were minor Germans at the TT.
Cheers
Michael