CDM only when qualified, usually with diploma level in asthma, COPD, CHD and/or diabetes. Some practices will get their nurses doing chronic disease clinics without the training or courses but I personally wouldn't and haven't done this. It's massively complex and ticking a box for QOF just isn't good enough even though the docs may expect it.
Bloods depends on your local provision - my surgery has a daily phlebotomy clinic so I don't do many bloods, just enough to keep my hand in. However I worked in a surgery doing maternity cover where the first hour of my clinic each day was bloods!
It's very varied and depends whether you'll be a treatment room nurse which tends to be the more routine stuff eg dressings, suture and clip removal, ear washouts, BP checks, health promotion, pill checks, ulcer dressings, vaccinations. Or a practice nurse which tends to involve more CDM, all contraception, cervical cytology, dopplers, triage and minor illness assessment, baby immunisations, travel health.
There is no one way for practice nursing, it all depends on the practice and the GPs. You're employed by them and not the NHS so they call the shots. What they will ask of you depends on their current team set up and their requirements. Good luck!