About a year ago I bought some surface-mounted 12-volt halogen
downlighters
from a well known mail order company. There are 7 lights, and at any given
time 3 or 4 of the darned things aren't working.

Use slimline fluorescent tubes. They give a much wider pool of light, which
is good for preparing food. You can also get a lot more total light output
without needing to construct another belching power station to power them
all.

I have 4 18W tubes under cupboards and a 30W tube up the chimney for the
cooker. That's 102W. Using halogen, due to reduced efficiency and their
inappropriate lighting pattern requiring many extra fittings, similar light
coverage would be getting on for a kilowatt, probably making the kitchen
unbearably hot in summer, too.

Christian.