can someone tell me if you enter three unlock codes at one time and two at another does that constitute your five attempts and the phone lock up? or is it five in the one go and the phone locks up?

Assume you mean for a nokia. 5 incorrect codes ever.

so even if i were to switch it off after entering 3 codes and then switch it back on I'd only have another 2 chances? it doesnt re-set back to 5 chances?

That's it, you've got it.