Welcome Peter, Good to see your still sailing your boats.
With regards to the black bailers, all I will say is they are c..p! I have told Richard to his face so no need to think im telling tails!
They just are not good for the job and i did not have them fitted to my new boat when I ordered it.
I have been told that the plastic ones are safe on the hands if you have to handle them when under the boat but we used the others for years.
Also that a customer wanted to sue a builder who fitted the stainless ones and so they are fitted just in case. So the story I was told went.
Only problem is they are bigger than the stainless ones and so you would have to come up with a way to fill the gap around them if you want to fit stainless.
I think that not many of the new Mk4boats at my club of which we have sixteen have not had a problem with them in one form or another.
See you on the water Peter and i hope you find a way around this problem.