https://en.wikipedia.org/wiki/Dennis_Specialist_Vehicles#Transbus_International

＞Dennis Motors, Hestair Dennis, Dennis Specialist Vehicles, Hestair Specialist Vehicles and just Specialist Vehicles but finally Transbus International was dissolved on 19 June 2018, after several times being restored from dissolution since 2008.

2018年に解散したと書かれていますね