Robin brought his "Exige formerly known as orange" and I had a go at restoring it to its former glory.
Before...

After...

Unrecognisable!
Top tips from Lawrence:
- always wash from the top down
- use a tall bucket (helps the silt sink well to the bottom)
- rinse the sponge well along the way
- stop before getting to the grimy areas and hose well as you go
- wipe the grimiest areas only once before rinsing both the area and the sponge
You can see the difference!
Campbell