Dim high level brake light R56

[Boogs]

My sons R56 MCS has a very dim central brake light. Not individual lights but the whole thing. All lights still work, just very dim. I think it has gradually been getting worse and now advised on MOT. Before I start replacing bits (would start with the actual light unit) has anyone else had this or has any ideas?

Thanks

[Elliot2000]

Yes, normally the lamp unit

[Boogs]

Known issue them, thanks