Downlight flickering

Wonder if anyone could give me some advice.

Have a newish house and one of the downlights in the upstairs corridor has started flickering.

I thought I could just replace the bulb like the downlights in the kitchen but this one seems to have the bulb as part of the unit. Here's the model:

Anyone know the reason for a unit where you can't replace the bulb??

So do I have to take it out of the ceiling and wire in a new unit?

Thanks!