Robert and Carolyn Hubbard booked their holiday through Vivair Flights, a travel agent based in Croydon in Surrey. Their holiday was booked for the end of July and the beginning of August.
They were advised by agents that it would be best for them to hire their car in the UK through Car Abroad, a car hire company based in London. The car was paid for through a pre-paid voucher system.
The voucher cost them £348, roughly the equivalent of $522. When they arrived at their destination they found that they could have hired the car for the same amount of time for only $420.
Mrs Hubbard said: "We effectively paid $100 over the odds simply for the convenience of booking it through the UK. The cost of a single telephone call or fax to make the arrangements could not have exceeded £5, so the rest is sheer profiteering."
The Hubbards complained about the difference in charges to the travel agent, which passed the letter on to the Travel Advice Centre, a company that deals with complaints. The couple wanted a refund of the difference between the local hire and the price paid in the UK.
After investigating, Linda Alliston, the Travel Advice Centre's managing director, decided that it could not offer a refund. She said: "Any business has many different overheads for marketing, administration, sales, agents, commission - which have to be costed out and added on to the rates achieved by the bulk buying capacity the company has."
Ms Alliston refused to comment on how much the commission would be on the car hire.
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