Many thanks for your replies guys!

We went and got a new bulb and put that in so hopefully itll be on its way
to clearing.

What had happened was that the fish in the pond were spawning and the water
had become very "polluted" (fine as far as dangerous chemicals go) but it
seemed that the algae was feeding on what the fish has done to the water,
maybe it was coincidence though...I only have 3 years of ponding experience
so far.
Anyway mum decided to replace around 2/3 of the water in the pond which im
not sure was a great idea since the algae in there fed like mad and made it
as much of a pea soup as it was before.

[Ka30p] - That "algae checklist" is wonderful, ive emailed it to my mum and
she has it printed out.

Thanks again for your great help!

Many Regards,

Dan