iPhone 4 lock button

[FlameR]

Has anyone else experienced a dodgy lock button on their iPhone 4. Mine is fine, and has a 'click' feel when pressed (as you'd expect). But I got my Mrs an iPhone 4 as well, and when you press the lock button, it doesn't have the same 'clicky' feel, and feels asif it doesn't even move when you press it!!

Any ideas? or is it a trip to Manchester to get it looked at/replaced!