We are seeing a lot of donors who have the "Gift Aid UK Only" field set to 1 but have no corresponding address details i.e. all their address fields are blank.
This is something quite a few other organisations are experiencing at the moment and it is something we are looking into.
This is an issue with Facebook's Transaction Reports and when we find out more info we will share it with the GivePanel community.
In the meantime, you can report this to Facebook directly.