Lesley, hang fire until you go to your local spinning group. It's usually not too hard to come across nice fleeces, and/or recommendations of where to get some.
You could also ask on Ravelry. I bought my Teeswater lambs' locks (as in the stove-top rainbow-dyeing post) from sheersheep on there - beautiful fibre. They were straight off the lamb, hence dirty - so lost a lot of weight on washing, so take that into account if buying fleece by the kg direct from the sheep. Michael usually has a few fleeces available so you could PM him directly.
Someone's recently posted in UK Fleeece People, on the "For Sale - fleece" thread, a list of fleeces about to be available - and she's going to check them herself before confirming their availability.
Ravellers would also tell you if they've had good or bad experiences with any proposed eBay sellers too. I bought some washed Southdown on eBay and it's sound as a pound
The seller was allinaspin; he seems to just have tops at the moment but no doubt will have fleeces again later in the season. I've bought a variety of tops from him too and they've all been superb. ETA and having just checked if he had any fleeces for you I've bought rather a lot of the tops he has on BuyItNow sale... How did
that happen???