Valuing combined rewards & equity in crowdfunding?

A friend owns a small vineyard and wishes to find individuals who will each receive a case of wine every year for 10 years; and also receive an equity stake.  In return, they would pay an up-front fee.  (This way, distribution is sorted, he has a loyal band of fellow-enthusiasts, and he can just concentrate on producing better wine). Whilst I understand that the rewards element is liable to VAT, what discount could be applied to this forward-buying committment?  For example, would HMRC consider it reasonable that the value of the rewards was, say, 33% less than the retail price of the wine? (When Chapel Down wine crowdfunded, I think they offered equity investors a 33% discount on list prices).  Also, I'm a bit confused about whether the two elemets can be conditional upon each other:  if you have to buy the equity to get the rewards, then might HMRC say that the whole 'investment' was liable to VAT?  (Maybe it works better if they have to buy the wine to qualify for the equity).  Ideally, the owner would like to find a way of offering both equity and rewards whilst minimising the VAT element.  I would really appreciate any one's thoughts on any of this,  And because most of the money received would be booked as income in year one, is it likely that HMRC would allow the profits to be off-set against the costs incurred over the following years?  Or would establishing a new limited-by-guarantee company (a membership club) be a better option? Apologies for asking so many questions here, but I've been unable to find anuy guidance on this...