You need to ask this of some academics in your old department. It's a question at least 50% of students on every course have and they've got nothing to lose by being quite open with you. If you gat a positive - 'yes, we'd love to see you back', then there you go. If you get 'It would be nice to see you again, but funding is tight, I think everyone this year got 85% or higher' then there's a hint that you'd need to find external funding, but they'd consider you.
I'd say it's worth a shot at both, if you have a well worked up, interesting research proposal. You stand a good chance of an offer, but funding might be tricky from either Uni.