I have done the p/t LLB elsewhere and it's quite manageable - even if on occasion it means cramming at the last minute.  When I first started, I had the perception that one had to spend hours upon hours memorising volumes of law books every week, but this is not the case.  

I try to attend most lectures and do the reading and tutorial notes in advance when I can, but the reality is it's not always possible with a full-time job (and a life!) - don't worry.  I tend to be lazy to begin with then end up cramming for coursework and exams, but if you're organised I'm sure it's far easier.

I've a friend (now a lawyer) who did the p/t LLB somewhere else again and had similar experiences.

Go for it.

Napier.  You'll be grand