If Psychology is your main interest, you'd probably be better off specialising later on (if you're interested in postgrad study).
PPE does sound like it'd be a good fit for you, provided you're interested in Economics too.
If not, I do know of a few joint hons Politics and Sociology courses- Bristol, Warwick and Newcastle do them. Politics and Philosophy/ Psych and Philosophy are also combinations I've seen around. My friend currently does Politics at the University of Essex, apparently the department there is fantastic, so you might want to look on their website. Good luck!