Ignore the photos and read the listing

Wide-angle photographs sell a lot of apartment hotels in London. The good ones, though, tend to be those whose listings answer a few dull questions: how big the flat is, how often it's cleaned, who's on the desk, how far it is to the Tube, what the kitchen really has, and what happens if you want to stay on.

Floor area, the kitchen and cleaning

Interiors get shot with wide lenses, and a sofa photographed from the doorway can make a box room look like a lounge, whereas floor area can't be dressed up. If a listing doesn't give it, ask, and compare your shortlisted flats with each other rather than with your memory of a hotel suite.

Listings say 'kitchen' for everything from a full room with an oven, dishwasher and tall fridge to a two-ring hob and a microwave in a cupboard. Look for the oven and the dishwasher in the pictures, because if you're planning to cook most nights, a kitchenette will be driving you mad by day three. Cleaning needs the same close reading. Daily service is rare in apartment hotels and serviced apartments alike, weekly is normal, or twice weekly on shorter stays, and the listing should say which. If all it says is 'housekeeping available', assume there's a charge.

The desk, the Tube line and the extras

Only about half the residences we list have a reception or front desk. The rest use key safes, door codes or someone meeting you at the flat, and neither approach is wrong as long as you know which you're getting and, if there is a desk, whether it's staffed round the clock or until 8pm with an on-call number after that. A late flight and a daytime-only desk is a combination to sort out before you travel.

Nearly every listing claims to be close to a station, and most really are, with almost every residence that has a known postcode within about ten minutes' walk of one. The better question is which line. For Heathrow, the Piccadilly line runs direct from Green Park, Knightsbridge and South Kensington, and the Elizabeth line from Paddington, Bond Street and Tottenham Court Road. If you're looking at apartment hotels in Kensington, South Kensington station has the Piccadilly, District and Circle lines while High Street Kensington has only the District and Circle, and you'll feel the difference on a Heathrow run with luggage.

Air conditioning, a lift, a gym, parking and a pool each turn up in some buildings and not others, a pool in only a handful. Decide which one you can't do without and filter on that first, since a pool you swim in twice isn't worth a worse Tube line for a week. When a listing says luxury, look past the word: the better luxury apartment hotels in London tell you what the linen is, how often it's changed and who answers the phone. Branded apartment hotels are built mostly around studios and one-beds, so if you need a 2 bedroom apartment hotel in London you'll find more choice among serviced apartment residences, where most buildings have two-bed flats and plenty have three.

Questions to send first

Send the same dates and these questions to two or three residences, then compare the answers line by line. A good operator replies by return, and slow or vague answers are informative in their own way.

• What's the floor area of the flat you're quoting for?
• Is there an oven and a dishwasher?
• How often is it cleaned, and is the linen changed on the same visit?
• What are the reception hours, and who answers at night?
• Which floor is it on, and is there a lift?
• What's the deposit, and when do we get it back?
• Can the stay be extended, and at what rate?
• Is the operator accredited, for example under ISAAP, the serviced accommodation quality and compliance scheme?