The Windsor Castle -http://www.thewindsorcastlekensington.co.uk/, which has now re-opened following a refurbishment, is holding a Real Ale & Craft Beer Festival in its beer garden, promising "22 Taps, a Huge Bottle Range and Food and Beer Tastings".
The pub itself dates from 1835, when it served as a stop-off point for livestock traders, and is full of character, featuring the partitions with small access doors still occasionally found in pubs of this era.
The nearest underground station is Notting Hill Gate. Take exit 2 for Notting Hill Gate (south side) and then, having passed both the Gate Cinema and the Coronet Cinema, take the next left into Campden Hill Road and you'll find The Windsor Castle a couple of hundred yards up the road on the left-hand side.
The festival is probably not going to work very well if it's raining and I've no idea how busy it's going to be, but if there are any problems we can easily head for the nearby Churchill Arms -http://churchillarmskensington.co.uk/. Please take a note of my phone number so that you can be sure of finding us if you're going to be joining us later on.