Update:
Called into my Honda dealer this morning. They looked, checked the records and because it was a replacement screen due to delamination and within warranty, they directed me to the company who replaced it.
Although the replacement is a genuine Honda screen, it was fitted by a local company, as my dealer doesn't carry out that type of work.
So, fortunately the company is only about a mile from my dealership. My dealer had phoned them, and told them I would bring it down for them to look at.
I took it to the screen company, and after they looked at it they responded with 'It is the weather, and we are seeing a few like this'. They said that the rubber seal along the bottom of the screen is actually supplied fitted to the screen by Honda at the factory, and they only clip the whole thing into the plastic trim. The only rubber seal they fit is along the sides and over the top. He said removing the screen, cleaning the algae would only be a temporary measure as it probably would come back. He said it would only be on the very edge of the underside lip, and would not extend further into the cabin. He said that as the weather warms up, and gets less damp the algae will die and probably be less conspicuous.
So, the upshot is that now it has been recorded, photographed and logged with my dealer and this company, I will wait and see if the mould spreads, or indeed does diminish in the warmer weather.
