Do we know for what reason he was sent back to prison for?

Dean has basically been set up by the police; arrested and charged with something he obviously did not do and has been blown out of proportion. I am not in the position to talk about the new case, as it is down to Dean and his co-accused to comment if they wish, however it is apparent that this is being used as an excuse to 'lock up another activist'.

With regards to the Highgate Four, those who are on license have had their rights comprehended to an extreme limit by the National Probation Service, Prison Service and those pulling their strings, ie NETCU and the NDET. For example (no longer in the case of Dean), they have to get permission to protest and are not allowed if it is refused by the NPS.