I see you've added re. the huddled builders "and one has developed a cough in the past few days." to your original post.
As noise is your issue "The point of my original post was about the noise" perhaps speak to the noise people at the council. I'm not sure they can deal with the noise of coughs though.
In regards to the virus: "Construction firms split as shutdown calls grow" [www.bbc.co.uk