Hey,
I'm not PPP, I'm ordinary Experimental Psychology, but we all have Psych lectures together. Doing PPP is much more work than ordinary EP, especially Physiology, as you have more lectures and afternoon practicals.
In first year EP you sit three exams at the end of Hilary Term (Psychology, Statistics and Neurophysiology), however if you do Psych and Phys you only do the first two, then sit your Physiology exam at the end of Trinity. Then you'll pick options for second year, and you won't do as many Psych options as EP students.
In the UK, the British Psychological Society accredits undergraduate degrees the Graduate Basis for Registration. If your course has this, you are eligible to do a postgraduate course to become a chartered psychologist (of any sort). If you don't have GBR, you have to do a conversion course. There are certain Psychology options you have to pick as a PPP student in order to still get GBR, but you get given info on this.
Does Sweden have an official body that regulates psychologists? If they do, I'd email them and ask if they would accredit the Oxford course. Although you may not need anything like GBR to be a psychologist in Sweden, I don't know, so have a look on their website, if there is such an organisation.
As for future career options in physiology, I don't know really. Some people go on to do graduate medicine I believe (which is half the time a normal medical degree takes), but other than that, the Oxford prospectus might be able to give you more details.