No. Gift Aid is about donations. There are special rules that allow Gift Aid to be claimed on membership subscriptions, even though they are not donations. These rules do not apply to paying for services.
So if someone pays a fee to attend a workshop, for example, that fee cannot have Gift Aid claimed on it, as it is a fee for a service, not a donation or a membership fee.
If access to the workshop was on a donation basis – and it was a genuine donation basis – i.e they could attend for free if they chose not to donate – then you could claim Gift Aid on the donation made.
