However you would not need the deductive powers of Sherlock Holmes to work out that Thomson is the favoured tour operator. Of the 156 brochure 'facings', one-fifth are devoted to Thomson brochures. The Thomson products also get pride of place, situated at eye level to grab the attention.
Of the remaining facings, Owners Abroad accounts for 15 spaces and Airtours has 10. This means that the three biggest tour operators have one-third of the available space.
In all, the office promotes only about 50 operators, including ferry and cruise companies - probably less than 5 per cent of the total number of companies offering inclusive package holidays abroad.
If you cannot guess the commercial links from the brochures on view, further clues are provided by the counter staff. A recent survey carried out for the BBC programme Breakaway checked on 11 Lunn Poly agencies: in all cases, inquirers were offered a Thomson holiday. At Airtours-owned Pickford, an Airtours package was offered 9 times out of 11.
The promotion of 'own brand' products has intensified since the Airtours acquisition of Pickfords. Airtours began an incentives war by offering all Pickfords counter staff a pounds 3 bonus for every Airtours holiday sold. Thomson followed suit.
The main multiples make no secret that they restrict the range of products to those operators prepared to pay extra commission. Operators wishing to sell through Lunn Poly will normally have to pay commission of up to 15 or 16 per cent, compared with the industry standard of 10 per cent.
Some independent agencies, however, believe it is their duty to offer consumers as wide a choice as possible. For example, the Real Holidays travel agency in London's Essex Road 'racks' more than 600 tour operators. Philip Davies, the owner, said the role of agencies like his was to represent the smaller specialist tour operator who is not racked in the multiples. 'We believe we offer the sort of good impartial advice that consumers want,' Mr Davies said.
But Real Holidays is unusual. Small specialist tour operators are increasingly aware that the only way to develop sales is to sell direct. For those prepared to scour the classified columns of newspapers, the choice is growing - for the consumer who patronises the high street agencies, the choice has never been more limited.