Hi Sally,
My simple head says that the ewes are still registered, but are just owned by somebody without a flock registration. If I were to buy them from you, I could still add them to my pedigree flock, so MV considerations apart, I don't see why that would affect their value? (I take it you still have their registration certificates?)
At the
Zwartbles Society auction in Stirling a few weeks ago, I picked up a 2-crop Z ewe for 80 guineas, plus two really nice gimmers and a ewe lamb for 200 guineas each. These were all very good quality MV accredited pedigree sheep. The sale was very slow though, and these values were a long way below what I've seen at other sales. Anything with obvious flaws didn't sell at all, and most of the very best stock failed to reach their reserves.
The averages of those which did sell were 112gns for flock ewes, 266 gns for gimmers and 152gns for lambs. The range for the lambs was between about £100 and £400 IIRC.
So, at a guess, I'm going to say £100 to £150 for each of the ewes, depending on their markings, plus £75 (i.e. basically meat value) for the cross-bred lambs. Your mileage may vary of course, and the simple answer is as always, 'whatever somebody will pay for them'.
Do you have any photos of the lambs? It would be interesting to compare them with our, ahem, Zanx Loaghwarts.