Found them.
Mostly Latinos with full face pics which means that they aren't bothered if they get recognised as they have no family over here, probably all working on the same premises too.
Looks the area is still being targeted by pimps/gang-masters, the last lot was a huge influx of Romanians and now it looks like South Americans or Spanish. What are the Home Office/Police doing while all this is going on under their noses.