However, to keep them coming back, hoteliers have been tweaking their product, considering cultural sensitivities and working to understand a new generation of Middle-Eastern visitors.

Having found that their Gulf guests like to experience specialised restaurants in the local area rather than frequent in-property venues, Hilton Park Lane are extending opening hours of food and beverage outlets, and adding 24-hour room service with Arabic menus to entice them to stay put.

Middle-Eastern tourists make up one in four guests at Hilton Park Lane, a third of which are from the UAE. The property has seen visitor numbers from the top five Middle-Eastern markets grow by 21 percent year-on-year.

Already serving halal meat across the board, Piccadilly property The Athenaeum found that one necessary adaptation for this emerging market was the inclusion of bidets in the bathrooms.

The Middle-East is a 850,000-pound-a-year market for The Athenaeum. Its director of sales Stephen Fox thinks that smaller hotels like his are doing especially well from the Gulf because some guests want now to "let their hair down" when in London. Privacy and anonymity is therefore of paramount importance.

"The Dorchester and the Jumeirah hotels meccas for Middle-East visitors to London -- there is increased interest in exploring some of the lesser known more private hotels," thinks Fox.

Asked to respond, Jumeirah Lowndes Hotel general manager Ian Richardson said, "We have seen no significant shift in business in Jumeirah's two London properties." The Dorchester declined to comment.

Most hotels questioned for this piece were reluctant to hand over exact figures for Gulf guest arrivals, but VisitBritain figures show that there were 33 percent more Saudi visitors to the UK in 2011 compared with a year earlier, and 11 percent more from the UAE. Zoom out to a five-year comparison and you get a 60 percent increase in Saudi guests and 36 percent for UAE nationals.

It is not just the sheer number of Gulf guests that will have West-London hoteliers' attention. According to London and Partners, the capital's marketing agency, Saudi Arabia and UAE visitors' average spend was £1,770 per person last year compared with £600 average for all markets, from the first to third quarters. This rose in the first quarter this year to £2,626 for Saudis and £1,194 for UAE.

But hotel booking patterns appear to be changing for the Middle-East market, and hotels can no longer expect full-price rack rates to be picked up by their oil-rich guests.

Ahmed El Barkouki, international sales director of The Savoy, where 10 to 12 percent of bookings hail from the Gulf, argues that though younger Middle-Eastern travellers still book higher room categories, especially the royal and presidential suites, their behaviour differs from their parents' generation.

"They are very savvy in comparing prices and getting the best deals, so rate integrity and constantly engaging this generation is very important."

Stephen Fox travels to the Middle-East once a year to meet clients. He says, "Now they will sit with their iPads with their mates in their palace and compare the rates on Bookings.com with the rates given by the hotel."

Hilton Park Lane's general manager Michael Shepherd reaffirms that though the discerning Gulf guest likes to feel they're getting value for money, "they like to be comfortable and their requirements are usually to have rooms that are connecting as they often travel in large family groups."

All hoteliers interviewed agreed that facilities, though important, come second to a sense of welcome.

Ahmed El Barkouki is the managing director of Caviar Black, a consultancy which seeks to help hotels attract high net worth clients from emerging markets. He highlights the importance of a hotel's sales team understanding guests' "cultural background."

At the Savoy, culture training is given to all new staff, so they can better interact with guests from emerging markets, and El Barkouki argues one of the Britain's strongest assets is its tolerance and integration.

"This plays a huge part in making all the Middle East travellers always feel safe and comfortable travelling to the UK."

(This article was corrected on 13 September with updated comment and figures from The Athenaeum hotel)

(Editing by Mark Kolmar)

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