Sam, I understand where you are coming from, and have too much respect for you and yours to get too grumpy about this. Though I confess it stings a bit that I am to be excluded simply on the basis of age (I am 50). Still, I am a proponent of doing whatever it takes to bring young people to folk, so my absence will be a price worth paying in order to achieve it. But may I suggest you reconsider two other elements in your invitation:

a) the emphasis on "skilled", especially as you use no basis for judgment (degree from a respected music conservatory, for example). I know, I am a bit extreme, but who will judge in advance whether someone is sufficiently skilled to attend? Nobody can, of course. Put yourself in your invitees shoes: How will they feel? Will some be too shy to risk being laughed at for being unskilled? Will some baulk at the elitism of the message and say "sod it"?
[This is not an idle comment. My daughter Aliki, who is 18 and sings and plays both Greek and English songs, has just considered your invitation and dropped it on both of the last two counts]

b) The price differential for British Isles participants. First - how will you check? Will a foreign-sounding name be enough? Age apart, I'd be in at the cheap price then given my surname, although I live in the UK (and I can easily provide a foreign address for correspondence, if that's all it takes). And is such a differential (almost double the cost) fiar, or will it be prohibitive? I know you are trying to attract participants from across the water, but while you incentivise some, you could be disadvantaging or putting off those near you. There certainly is no real basis for the price difference - UK based people will not cost you more to admit, after all. Perhaps some other way can be found to provide incentives for those from further afield?

But I honestly do not want to rain on your parade. What you are trying to do IS GOOD, and I wish you and hope for every success in the venture. It's a good basis; just a couple of rough edges that might welcome some smoothing...

Good luck