Okay, having scoped the site (or, ah, failed to cram into the back of the panel I was intending to go to), here's the details for anyone who actually wants to sit and chat with me for a while at LonCon. This will work for both con attendees and non-attendees as the main 'runway' of the Excel Centre is open attendance and anyone can wander in quite happily.
For those travelling in, get off the DLR at the Prince Regent station and head into the east end of the Excel centre. Not far in (opposite Hall N11) is an "Andronicus World of Coffee" shop. They have an upstairs seating area/balcony (stairs at the back of the downstairs seating), and I will park myself up here (near the piano) from 10.30 am to just before midday on Saturday (16th). I'll be wearing a red and black shirt - and the name tag should give me away (plus it's quite quiet up here so I might be the only one present).
Note: the Excel Centre main runway retains heat real well, so layers you can shed are probably a good idea.