Just saw this advertised on the CCH website: http://www.computinghistory.org.uk/det/43210/Retro-Computer-Festival-2017/.
An entire weekend dedicated to the Retro Computing Community. The Centre for Computing History will be opening it's doors on the 16th & 17th September 2017 and welcoming enthusiasts to exhibit their personal collections, retro computing mods and hacks.
The event is still very much in the ideas and planning stage, but if you would like to be involved as an exhibitor please do contact : firstname.lastname@example.org
I know we do a lot of stuff at the CCH but perhaps an ABUG exhibit is in order? I will certainly go along for the weekend.