Exige_240R
Exactly, 'Welcome to Yorkshire' have been advertising the county for a while now, and manage to advertise some big-budget events worldwide such as the 'Tour de Yorkshire' and various different markets across the county. I even visited their HQ in Leeds a few years ago for a university project.
Yeah that always fascinated me too regarding the plate codes. It's interesting though, as I often see London-registered buses in York, which were previously used in London before being used here, plus because of the manufacturer registration, you also see Scottish-registered buses in Brighton too.
Often you may see buses/coaches with Yorkshire plates affixed too, as there are multiple bus manufacturers in the region, such as Plaxton (Scarborough) and Optare (Sherburn-in-Elmet, Leeds), plus the main importer of Van Hool, VDL, BMC, Otokar, Yutong, Scania-Higer buses is based near Castleford, so they just register the buses at the nearest office.