PAVA, or pelargonic acid vanillylamide, is an incapacitant spray dispensed from a hand-held canister. Many British police now prefer it to CS gas. I doubt Dave would have been allowed to use it back in the sixties!
Pepper spray is a great idea. Can't believe it wasn't invented sooner. Those big pepper grinders are so bulky.
Cambridge and Oxford were referred to cryptically by the Small Faces on the song Itchykoo Park (possibly misspelt)