Not at all. Monarch, Thomas Cook and Thomson all regularly fly widebodies on short haul routes.
The first widebody I saw on short haul was back in 1970 at PMI.
Condor were using their new B747's from Cologne to PMI about 2-3 times weekly on charters.
and don't forget Court Line operating for Clarkson Holidays
Thanks for all of them. It wasn't what I asked though:
Would this make Jet2 the first low cost carrier in the world to operate wide bodied aircraft on short haul operations - assuming they acquire 767s and are put on European routes?