On Sunday, 1 December 2019 19:46:48 UTC, rick wrote:
Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I don't think it's down to makes. A company eithe rmakes dimmable or non-dimmable they can make both, dimmable are usually more expensive.