Ubik on fake wood panels

I have a job job to clean an entire house front cladded with this wood effect panelling - I was going to use Ubik 20:1 mix, to remove the green stuff - is that going to be okay on this material or should I steer clear of using it ? I tested a little and it seems the panels are pretty flimsy in terms of the wood effect layer (noticed a couple marks after brushing my house and it’s my neighbours place I have to clean).

Also noticed some some marking on the cream angle trims after cleaning. I looked and all properties had signs of marks on the trims but they show up more after cleaning. 

Plan was to use a WFP and brush to clean the soiling but now I am not sure the Ubik brush is the best technique - just feels like a possible pain in the **** job if it goes wrong, but £50 for an hours work is obviously not to be sneezed at ?  any tips welcome thanks in advance

Looks like it’s the latest cement cladding board , we use Virosol but ubick is similar and at 20-1 will be fine , if it’s green algy and you are used to using hypo I would give it a treatment with that as it will kill the spores ubick won’t