Flickering 2D light bulb

[Russell]

Mum has a bathroom light fitting that uses a 2D compact fluorescent bulb.  It flickers on and off for between 5-10 seconds on switch on.  I've replaced bulb and starter to no effect.  The only thing left is the ballast which is riveted into the fitting.  Scorched earth says just replace the whole fitting but could there be another reason?

Any thoughts?

Thanks

[Polar Bear]

My only thought would be to replace with an led fitting of a similar size and style.   A quick google shows a good range available starting at reasonable prices.