I applied for both Cardiff and Swansea in November last Year. I heard off Cardiff literally two weeks after applying. I heard off Swansea beginning of January.
Don't worry give it time I am sure you will hear back. Looking at most threads on Cardiff you don't generally hear how you did on interview until March April time.
They emailed me to say about my interview it then came through ucas. Cardiff followed up with a letter. Be aware Cardiff want you to send a reference back to them in the post before the interview. Not the details of the reference an actual reference. You also have to complete a fitness to practise and photocopy all your certificates and send it to them.
The interview was pretty straight forward in Swansea. Just make sure you read up on code of practise, wellbeing act, role and qualities of social, anti discrimination and oppression and there is a good website called social work interview tutor and it's got a list of potential questions you could be asked. Don't forget to read lots of books around social work and also some news on social work and Welsh contexted.
There not there to trip you up and your not a social worker. Your applying to become one, so don't stress to much.
What's your background anyways, why social work and have you applied any where else?.
Ask away on the questions, if I can help I will