X Type - Lights flickering

[Woody John]

Hi

The other half is very fond of her x type diesel.
The battery warning light has been on for near on 10 months without any outstanding issues.
Car starts great.

Recently the lights have started flickering inside and headlights.

Any ideas what the problem may be?

Id imagine if the alternator was on the way out the car would have stopped starting long ago.

Cheers