the SWG aircraft are on canadian reg, SWG AOC, Canadian pilots and operate under Canadian rules on TOM flight numbers.
The UK cabin crew have to comply with Canadian requirements, all announcements in English and French.
When I travelled last summer (BHX/AYT) the Capt went to the trouble of explaining how SWG was a joint venture with TUI and therefore SWG Airlines was a sister airline to Thomson.
When the aircraft go to Canada, there's a mix of "wet lease" on UK register and others that transfer to the Canadian register.