There seems to be a seat in the doorway on that. And the obvious gaps on the low-floor bus seem to be the wheelchair and luggage spaces. Even the emergency exit door's new location (thanks to new regulations apparently) seems to have more impact than the wheel arches.this is a 12m Plaxton Panther, http://tellingsgoldenmiller.hostinguk.com/images/seat_plans/Coach Plan 49 Seats Center.GIF
The wheelchair space on the Tempo seems to be the same size as the hole on the coach (I'm guessing that's either a toilet or a wheelchair space). Discounting the seat that seems to be in the doorway, the coach seems to have two rows of seats more than the Tempo. One of those rows is accounted for by the luggage racks on the Tempo. I can't figure out where the other extra row of seats comes from, are you sure that's a 12m coach plan not something slightly longer? It seems to map to the X1260 Tempo quite well, with the coach having one row of seats more due to lack of luggage racks on the coach. By the way this comparison is with the standard Tempo layout, and the legroom looks the same to me on the seat plans, so not quite good enough for a 2hr journey in my opinion.