It's not something they should really be asking in my opinion, they are not selling finance, i would deem you an assured tenant and so use that term on your info sheet, also, make sure you let them know you have a local vet that you have used previously and have a good relationship with, that's something else they will perhaps be concerned about as vets cost money and the rescue people may associate a 'tenant' with a restricted income, which of course is a stereotype response but can lead to assumptions.