Answer:
Do you mean do we call them travel agents or are you looking for the names of the tour operatore themselves?
Well we call them travel agents and some of these are: Thomas Cook, Thomsons, Ramsay World Travel, Co-Operative travel, Barrhead travel, Caledonia travel etc...etc... Depending on what you are looking for there are all sorts of different travel agents recommended under different groups whether it be a specialist cruise co-ordinator or just someone to book you a hotel, check on a flight!! hope this has been of help :)