HELP I left my books at home!!!

If you're not travelling with a Kindle, download the free Kindle app on whatever device you have with you (phone, Laptop or whatever). Once you have the app, download the RS London 2017 (currently priced at $11.69). I believe it's also available on iBooks and other formats.

The RS staffers can probably provide more complete information, but we probably won't hear from them until Monday, so I Googled and found the 2017 London guide on both of the following large retailers' web sites. That doesn't guarantee that they have the book in stock at their stores, but I think the odds are pretty good. I suggest calling ahead before venturing forth.

Above edited to specify the London guide book rather than the GB guide book.

Stanfords, 12-14 Longacre, London (Internet says it opens at 11:30 AM)

Waterstones, 203-206 Piccadilly, London (Internet says it opens at noon)

Note: I haven't verified those opening times.

YOU GUYS ARE AWESOME!!!! Thank you SOOOO MUCH!!! I will update you on my successes.

And for some reason if they don't have them, check Foyle's Books on Charing Cross. I believe it is still the largest bookshop in London. They also have an online search for in stock books.

I still remember the old days before remodeling when you could get lost in little nooks all over the place. Now, it's orderly.

The other idea would be to open an Amazon.co.uk account. (Easy to do if you have Amazon.com) and have them deliver it to your hotel in London. It will be waiting for you. I've done this and it's easy. If you have Prime delivery could be the next day.

I have seen Rick's books at Stanfords, including both of the ones you are looking for.