2018 calendar

that's a bank holiday weekend for next year

The UK doesn't really have conventions as you have in America. There is only one similar centre, ExCel in Docklands plus the smaller Olympia in west London. ExCel hasn't launched its programme for May yet and even if this were full, it wouldn't be large enough to have a significant impact on room availability.

The Bank Holiday will have a significant impact, as you are already finding 10 months out!

Conventions are more likely to impact on towns & cities outside of London. For example the main political parties have big conferences each year autumn but they tend to go to Brighton or Blackpool or to a big regional city like Manchester or Birmingham.

A big convention in London (the Ideal Home Show in March is one that springs to mind) would probably only impact on hotels in the immediate area - in this case, Olympia in the Hammersmith area.

Bank Holidays and school holidays have more impact - and late May is generally both a BH weekend and the start of the weeklong half term break for many schools.

Thanks everyone! I totally forgot about the bank holiday in May. I thought it was really strange finding several hotels with no availability but now that makes sense.

I had the same problem reserving rooms at a B & B in Ireland for next May. The on-line booking sites said "no availability for those dates". I used google to find the e-mail address for the B & B, and contacted them directly. They did indeed have rooms available. I don't know why they weren't shown through the site.

I was told by someone in the travel industry that on line booking sites have only a certain number of rooms at hotels. That's why when you try and book a room on Hotels.com and it says no availability, you can often pick up a reservation on, say booking.com. Which is why I prefer to use an online site to research hotels and then make a reservation with the hotel.

I found some of the hotel sites only show available dates like 9 or 10 months out, so when I email them directly, they would email me back telling me when I could expect to see those dates become available. I'd set a reminder on my calendar and check again, and loads of availabilty appeared.
If the place is important to you, you might want to email them directly to see if those dates are booked yet or not.
Good luck,
-Alison

I thought it was really strange finding several hotels with no availability but now that makes sense.

I think it is likely that the hotel has not opened up booking yet.

Thanks everyone. Lots of great advice.