I just had my interview a few days ago with PDSA (I will find out if I get the job or not by tomorrow or Monday) and I found they make you feel very comfortable they are very friendly and very professional :) they also give you positive feedback during the interview as to why they invited you to interview in the first place
Plymouth - Would not advise people to join the Plymouth shop unless they enjoy working on one task every day. Manager can be quite rude.
As with every interview. Dress smart. Research the company and be yourself. Enjoy the interview and gain experience from it.
Ask. if they are looking to hire, then you can fill out a really simple and non invasive form then they'll requte you