Not seen it mentioned here but I've just finished reading the article in Guitarist about the Brian May pedal.
It states that they listened to the master tapes of WATC and WWRY and found bits that were left out of the final mixes.
Apparently the building feedback in the WWRY solo ends in a massive thrashout. - Brian says "wow sounds like I was enjoying that." and WATC has a comedy "shave and a haircut" ending. Brian says "that's why it only got to number two"
.
I bet these won;t surface anytime soon. Pity it sounds good.
Neil