Xenon bulb flickering

[Schotten]

Hi there, about 3 years ago one of bulbs went on my Xenon (OEM) headlights. As it's a pain to change them (bumper off light units out - unless someone says other than that!) I thought change both at the same time, got 2 from DMGRS all fine until last Autumn- every now and then the I/side would go out with the obligatory warning message in the IPK. Switched lights off and back on again, still the same. Turn ignition off and back on again, light unit works and message goes away. This was not a regular occurrence, not after going over a bump, checked wiring as best you can , all seems fine. Past few weeks it’s been happening more or less every day I drive the car, now the if just switch off headlamps and back on again whilst driving the light come back in and the message goes away. Past week I’ve noticed a slight flicker from the headlamp, then off it goes. Switch to sidelights and back to headlamp clears it, temporarily. Probably just a new bulb required? Again wiring checked when lights are on and the lamp unit out makes no difference. Strange behaviour?