I realise it's different here - but I actually placed an ad on the board that our Vet's office has.
I also placed an ad in our local paper, making sure I took up 3 references for the people that applied - going to those homes in person.
I also placed an ad on Gumtree (Surrey) and again took up references in person for the referrals.
I really wish you luck - I know how important it is to you and your Littlie
Sally + Harry x