I am traveling with my wife and son (infant) to London from Dubai. The flight lands early morning (6 am) and hotel check-in time starts at 3 pm. I contacted the hotel and they refused to accept an early check-in. What are my options to spend 5 - 6 hours after a tiring journey? I am looking for a place where we can relax a bit.
Your options might be either paying for the previous night, or asking them to keep your bags, taking care of the room registration, and heading to the nearest MacDonalds.
Some run down hostels might charge per hour, personally I would not want to be there alone, much less with an infant. You might consider paying the full previous night in a cheap B&B just to try to rest a bit.
The problems I see is that by the time you add taxis and the daily use of another hotel, it may make more sense paying another night and not moving hotels. Furthermore, you also have the added annoyance of dealing with luggage twice.
However, usually in the mornings people will be running all over the place for breakfast and with heavy luggage for leaving, also cleaning crews, and then the preparations for lunch time, so I doubt pretty much you will be able to sleep before 0300PM.
Considering you will be checking out of a big airport, get transportation to the center of London, and then go through the bureaucratic motions at the hotel, or even wait for a room, I would say that you wont get a room much before 0930-1000AM. You also will need to wind down from the trip and from jet lag, so again you wont be able to sleep/rest much.
At the end of the day, if it might mean only spending a couple of hours at a MacDonald´s, and winding down over a cup of coffee in a relatively family friendly environment, I would probably do it ( I did it last time I was in Manila with my wife ). If in a big chain, you may also linger for a while in their premises/lobby/coffee shop while making time.
Nevertheless, as a first approach, I would still try to secure a room at a discounted rate for the previous night. They will probably say they have the same expenses with you sleeping on it the full time or only part of the allocated time, which is mostly BS as for instance, often corporate rates are half of the full price - make it clear that if they do not offer a good discount, you are not getting a room at full rate. It might work if they are not fully booked; you might have more changes of getting that if asking to talk with the manager on duty.
In my experience, if you are staying at a large chain hotel, particularly an airport or business hotel, it is quite possible to be checked in very early in the morning. There are very few guests checking in at this time, but lots of guests checking out, and the hotel only needs to find you one room.
At worse, the hotel will take your luggage from you and put it in the luggage store.
I am struggling to remember any time I was refused an early check in---a few years ago in Dubai I arrived at the hotel at 7 am or so---I remember was on the first train of the day from the airport---and the hotel asked me to use the pool for an hour while they found me a room. I was in Buenos Aires a couple of years back and similar story, but that time hotel found me a small room for a few hours until a suite was ready. 95% of the time though it's not been a problem for me.
If you're staying at a small, non-chain property or a family B&B, these places tend to be much more strict with check in times.