Yeah, that's the strange thing. If I hadn't looked, I probably wouldn't have noticed. System boots with no issues and runs fine even when running games.
I know I cheaped out on the PSU but I heard good things about it and, due to my modest budget, the price was right!
I didn't want to have to go through the whole returns process as it's no fun but I think I might have to. It's only the fact that my system is otherwise operating normally that has made me a little hesitant.
Thanks for your reply, I will definitely check that PSU out.
The 2nd PSU was an Arianet 800w "Silent Gaming PSU". I know everyone here said to go branded but I was recommended the Arianet PSU by various people and on one or two forums so I thought it would be ok. It clearly wasn't.
Anyway, 3rd time lucky.
I've not bought and an installed an OCZ Modxstream Pro 700w. So far it is running perfectly with no issues.
I'm in the process of sending the 2nd one back and I think I'll have to just call this a lesson learned!