FF, could I suggest you post me a sample - say about half-a-pound - for me to see if I can spin it? If I can, it'd be worth getting the whole lot across. I'll reimburse you the postage - it would only be £2.20 on that size packet, I think?
I have a neighbour goes to Sheffield regularly to see her mum, so if we were going to bring the whole lot over, if you could take it to her mum's house, I'm sure I could arrange that she'd ferry it - she's that kind of person.
10% of the yarn sounds entirely reasonable - but I don't know how long it might take me to get through 6 fleeces .... I guess I'd send you back a little more than 1/2 what I spin from the first one, eh? That'd work!

Getting ahead of myself here...

... let me know what you think about sending me a sample over.