Trevor wrote:
Was thinking of getting a solar powered shed light for my Dad. Anyone
recommend any?

Reluctant to buy one that hasn't been recommended after solar garden lights
that dont work.

Of course it would really need to work at this time of year to be of any
use, which would I guess mean attaching to a car battery or similar?

I think you need a serious installation, not some pound shop gimmick.
Have a look here for panels and regulators:
http://www.bullnet.co.uk/shops/test/solar.htm

(there are others - they cost a lot. E.G.
http://www.selectsolar.co.uk/kit.php
http://www.windandsun.demon.co.uk/prices_pv_modules.htm)

Then stick in an old car battery and a couple of 12V flouro fittings.
I got mine from an ordinary electrical wholesaler, but the caravan and
camping people have them and so do Maplin.

You need to do some maths. If you have a 12W tube and use it for 2
hours a day, that's 24watt-hours. A 6W panel illuminated for 6 hours a
day will generate 36watt-hours if the sunlight is bright enough, more
than enough to replace it. In northern climes, a 24W panel may be
needed to replenish the battery in midwinter, but you could always use
a mains charger once a month from December to February.

For five minutes a couple of times a day, one of the packaged solutions
might be good enough:
http://www.maplin.co.uk/Module.aspx?ModuleNo=46668 for example. The
description here is very sensible: 14 hours charging for 45 minutes
light. I would expect that to drop to 15 minutes after two years as
the cell and battery age. Budget for a few minutes a day in winter.