Samuel O'Hanlon led the operation with Jack Sargeant, demanding money from customers before work was complete, repeatedly identifying new problems and squeezing home owners for cash.
Samuel Corner was one of four convicted of raiding defence firm Elbit's UK site and destroying equipment with sledgehammers and crowbars in a bid to shut the factory down.
Samuel Corner told his trial he brought the tool down on Sergeant Kate Evans after he heard 'someone screaming' and feared they were being injured by security guards.
Samuel Corner, 23, said he heard 'someone screaming' and believed another demonstrator was being 'seriously hurt', so brought down the hammer on Sergeant Kate Evans, fracturing her spine.