They were definately buzzards i would have been even more amazed if they were kite (the only one i've seen was very very high in the sky), unfortunately i didn't manage to get a picture due to pesky battery problems.
There was a lot of wing flapping and jumping around so as previously said i could only presume worms, some more investigating might be in order
As to the numbers we get lots in somerset but never so many in one place! The field was around 8 miles from lulworth cove and right near the road so a good spot.
Any more suggestions no matter how wacky would be much appreicated, thanks friends!