Don't know about "ex Yorkshire single deckers", but the compound was quite full of Temsa Avenues; the 17xx Darts were behind these, backing onto the bank at the very rear of the site. The 11xx Darts were generally at the side of the site, alongside the footpath / access road.

Based on the fleet list on this forum site, I was speculating about further Darts (from the 165x series) and the Volvo / Renown 4515, but I couldn't be certain what was there for the plethora of other vehicles around them!

(It was Bank Holiday Monday when I visited, so there were a fair few vehicles parked up, no doubt not required for service this day)