Gift Aid is a big deal for UK charities.
Generally, the way it works is that when a charity asks for a donation, they also ask the donor to tick a box to enable the charity to reclaim an additional tax element from the tax authority (if the donor is a UK tax payer).
Combined with a date field (which Wild Apricot doesn't yet provide!), we administrators could create a report/search query to pre-fill the relevant form to submit to the tax authority for the reclaim.
It's not clear what the suggestion is. You can use donation date as a date field, add custom checkbox field into donation form and use Export of donations after that to search donations that can be claimed.
Can you give more details on what you'd like to have in WA relating to this matter?