CallumSimpson :
I am from the UK and the budget is around £550 including a monitor. I was thinking of getting a fx 6300 and an r9 380.
You need a high quality 500-550 watt unit for those specs. These are the best options I can find of good quality without spending too much-
http://uk.pcpartpicker.com/parts/compare/antec-power-supply-hcg520m,antec-power-supply-tp550c,seasonic-power-supply-s12ii620bronze/