I just listed out who I flew with on the type; was surprised to get to 12
Conti Flug
Cityjet
BA
Euromanx
PSA
Aer Lingus
Jota
Air UK
Buzz
British European
Flybe
Manx
The only one with 5-across seating was PSA, which several US carriers apparently did, but maybe no Europeans. The seats were set somewhat higher, step up from the aisle, and because of the inward curve of the cabin wall there was no more real room than with 6-across set further down. The ones that later came back to Europe were reseated.