Was the donation optional?
(Just for clarity, are you the charity or a ticket buyer)
I am not a Charity just helping to raise funds for a local Charity.
No, but those who bought tickets knew the food was £5 to the Golf Club and The remaining £10 was for a chosen local registered Charity.
was the £10 an entrance fee?
The £10 was part of the ticket price with the knowledge by the purchasing members that it was a donation to the Captain’s Chosen Charity.
Full of information as usual.
Can no-one construct a query of more than one sentence?
The crucial piece of information missing from the query is what happens if some tightwad comes along and says he's not going to pay the £10 charitable donation ?
Fortunately, Which has extracted this information. If it's not optional, it's not a donation.
And if the net amount after vat is a donation by anyone, it's a donation by the golf club to the charity, so no gift aid either..
So to the OP, thank you for taking the time to raise funds for a doubtless worthy cause, I'm sure what evetr they do receive will be valuable to them, even if its not as much as you had hoped. With more planning or some advice you might be able to avoid some of these pitfalls next time. Organising events is one of the most costly and least effective ways of raising funds there is for this sort of reason. One tip: if you don't want to make part of the entry fee optional, then at least make sure that somewhere in the event, you have a chance to explain the worthy cause and invite/cajole/blackmail attenders to give even more directly to the charity...
What's crucial is whether you've more or less than one in six tightwads amongst your "customers".