A couple of things you may want to consider:
1) lost-doggies.co.uk - I think you still own the domain. Why not put in a re-direct to the new site?
2) You might want to consider narrowing your focus. For someone in North America, I would probably not post on your site if I had lost my dog. Maybe focusing on UK first, then expand?
Keep up the good work and may every lost dog find his/her home or a new warm and caring home.