We recorded accounts of dawn raids on site with no other purpose than to make their stoping in the area uncomfortable
One friend, a singer named Mikeen McCarthy's fifteen year old song was stopped by the police in London, told he fitted the description of a suspected burglar in the Midlands, and driven to Birmingham, where he was released without charge and left to make his own way back to London.
It was a regular occurrence for Travellers to be asked to "donate" to the "police fund" in order to be left in peace.
I was told by a work-mate that his brother-in-law and friends intended to fire-bomb an illegal stopping place on Mitcham Common.
I went to the police and reported the matter
Luckily I also went to the local Travellers site where a Gypsy Concil man was stopping - he organised a watch on the on the site and the raid never took place.
As far as we knew, the police did nothing, but three weeks after we had reported it we had a visit from a lone policeman whose main interest was to find out why we were "consorting with these people in the first place".   
At the time we were working with Travellers the overwhelmingly most common crime was driving without tax and insurance, yet they were subject to regular harassment.
The Gypsy Councilman I mentioned once carried out an investigation into the piles of rubbish on their site (the oldest continually settled site in London - George Borrow wrote about it)   
The G.C. man traced the fridges, cookers, abandoned cars... etc, directly back to local householders who were using the site as a rubbish dump.
Sorry to go on so long - it really does get me going.
Van - I really do sympathise with your position - I lived in London long enough to know first hand that you are not alone in your situation
Jim Carroll