Gaussfest, and an electrical day in London on the 7th September @ The London Museum of Water and Steam
https://www.extremeelectronics.co.uk/the-gaussfest/
High voltage, tesla coils, electrostatic machine demonstrations and another Victorian/Edwardian pumping station to look around plus a chance of seeing a working mercury rectifier(s)
I can't think of a better day out :)
Tickets https://lmws.digitickets.co.uk/event-tickets/68513?catID=65283&