Fire Hoods fit over ceiling light fittings and are being prescribed by more and more electricians.
The regulations have scared many of them into specifying them just to be on the safe side.
They are nothing to do with the type of light fitting, its the hole you cut in the ceiling that weakens the fire retardent effect of the ceiling.
The hoods cover the light fitting and repair the fire protection and that's why they are used.
These are 150 x 150mm so should cover the majority of ceiling fittings, certainly all the ones we sell!
Sorry about the picture, they are just not very photogenic!

aka. Intumescent Downlight Cover!
66 minute fire rating
Part E Acoustic Compliant
Tested to BS476 Part 23
Ventilated to reduce heat build up
Prevents fire from penetrating the ceiling void and retains ceiling's fire protection integrity.