As far as I understand, applying for transfers usually isn't subject to the January UCAS deadline but you need to check with each university you want to apply to to see if they actually accept transfers.
If you apply via clearing, that works, but I would avoid that - you can mount an UCAS application now and apply now to the places where you want to apply to. If you wait until clearing, then you can't apply to wherever you want, you need to apply to the places with spaces still, which may or may not be the unis that you want to go to.
But it seems like you're undecided on what to do and this isn't a decision that needs to be rushed - if taking the time to make this decision means going to clearing, then that's preferable than rushing to decide.