The key to this problem regardless if your in a union or not is for you and your colleagues to be singing from the same hymn sheet. make your complaints official and documentised you cant just have "little chats" the second they sack any of you for being disruptive or refusing to co-operate take them to an industrial tribunal. (although this may take some time as there seems to be loads at the moment) also please seek legal advice as officially theres no such thing as bullying at work, they have to call it something else (i cant remember what, its been a while since i studied lol) but ive seen people win tens of thousands in compensation.