Ok, so the rubber on my remote was crumbling.
Bought new rubber off the 'Bay and changed it last night.
No problems at all.
This morning the rubber has to be pressed quite a way in and the rubber got caught half way down - a bit annoying.
Thought I'd try and wedge something between the circuit board and the rubber to make it a bit harder.
Did that - didn't unlock the car, so removed it.
Put key back together and the red light was constantly on.
It shortly went out but now isn't unlocking the car!
Please someone tell me this is an easy fix and I don't have to take my tail between my legs to Peugeot and get it re-programmed?
)