Cleaning a glass roof.

[RickH]

Regardless of the cleaning solution you choose, be sure to test it on a small, inconspicuous area of the roof first to ensure that it doesn't cause any damage or discoloration. It's also important to use caution when working on a sloping glass roof, as it can be slippery and dangerous. Consider using safety equipment such as a harness or safety line, and never work on the roof alone.

I did mention I won’t go onto the glass - too risky.

 

[RickH]

Secure (duct tape, zip ties, whatever works best) something with a bit of weight to the back of the brush head?

Yes, I know these particular ones are out of stock, but it illustrates what I mean:

https://www.tesco.com/groceries/en-GB/products/301727319?preservedReferrer=https://www.google.com/

I have pvc coated scuba diving weights, 1 kg and 2Kg. So could try one of those