I've just had the same problem, found a couple of threads on here about it and I deduced from it that,
Castrol Edge 5w 30 is the correct oil, its pricey at £44.99 for Halfords but worth it. Annoying thing is for an oil change you need 4.6l and it only comes in 4l tubs for you need 2 tubs, that right £90 just on some oil!