we use pressure washer and long lance you can brush it with wfp but i have snapped one off so now only use pressure washer or conny ladder hire them in from hss £25.00 per day + vat
No need for this at all. If you already have this kit and don't mind setting it up, that's OK. Can you afford the time and cost of hiring a conny ladder? I never can.
You simply need to be careful and remember that
the scrubbing power is at the ends of the bristles - NOT the sides. So you DON'T need to press hard, so you won't knock the ridge capping off.
My way is to rest the pole on the edge of the conny roof so the brush is gently touching the capping and gently move the brush side to side, up and down and rotate back and forth. Remember again -
the scrubbing power is at the ends of the bristles. Then you move the brush along and repeat.
Depending on the soiling, it can be a little time-consuming, but it gets the job done. Pre-soaking (esp with a weak TFR solution) certainly helps.