Can anyone confirm whether as a PhD student you can take out a student loan. I already have a loan from previous undergraduate study.

No you can't take out a student loan for postgraduate study. You need to look at options such as career development loans or graduate loans. These do not offer the relatively favourable repayment options of an undergraduate student loan.

Nope and chances are you won't qualify for a career development loan (these tend to be reserved for professional qualifications - I couldn't get one for my Masters). Best thing to do is go into your bank and ask them what they can do for you - I took out a graduate loan for my MSc and the interest is much less than the CDL (although there was less of a break in paying it back)