Oh, I didn't realise there was a tornado in Bucks? Do you happen to have any damage reports etc.
Also, I am currently 50/50 whether it was a supercell. Some of the footage of it round Heathrow area showed some slight rotation. When I was there the storm certainly had some supercellular appearance characteristics but I didn't manage to get enough of a stable shot to note any proper rotation. In the middle of the storm certainly felt very intense, but as I was there I probably have a slight bias for it be the more extreme thing and for me to want it to be my first supercell, so I dont want to rush in calling it one if it is not really. But that being said, would not be surprised if it was found to be a weak supercell. If anyone has any thoughts, footage, anything interesting at all about this I would love to hear!