I love my Salvo-Knackers 9Ah 21W light (fully paid up fan club member, Phill!), but when I dived with Al recently (who I think has an 18W bulb... and I've given up trying to re-write the following so it doesn't read like some sort of gay porn...) I spent the first half of the dive moving my head in and out but nomatter what I did the spot his made on the bottom was so much tighter and cleaner than mine.
I'll get my coat... but while I do...
IIRC, the light from a 24W bulb I saw was a *little* brighter than mine, but nothing like as good as the 18W beam. The advantage does seem to be down to the different (cooler/bluer) colour temperature of the 18W bulb Al was using (though apart from the 10W, they all looked bright enough to me to get the job done).
So,I want one too now! Where can you get an 18W bulb from in the UK (Phill

?), and is changing the bulb just a matter of (carefully!) taking the cover off, pulling out the existing bulb and slipping the new one in, or do you need to change electronics or resistors or other stuff I'd not be happy to do with my scary-many-hundred-pounds-worth of light?
David