[loki_the_glt]

I spoke to one of the Cheshire members whose cars are ALWAYS immaculate about this.

His suggestion was to use a very hot water (and, optionally, car shampoo mix) and apply it with a soft tooth-brush to the rain-gutters/badges etc. A piece of thin styrene will work on the gutters if the tooth-brush won't fit.

It might take two or three goes to eliminate the algae, so don't despair if it doesn't seem to be working initially.