Thanks for the info Bryan and Derek.

I didn't know they made special floats
They are advertised in a Bennett's of Sheffield catalogue that was slipped
into one of the angling weeklies (Angling Times I think). The floats are
clear with removable orange tips. You put a Starlite in the float, then
shot it up as normal and start fishing. When it gets too dark to see you
remove the tip, activate the Starlite, replace the tip and carry on fishing
without the need to re-shot your setup. They sound like useful accessories
so I think I'll get them. Trouble is if I get many more 'useful'
accessories, I'll need a team of Sherpas to carry them all :-)