Good news - I’ve had all the connectors off and thoroughly cleaned every contact, and the screen is now working again. There’s a strange gradation of colour from one side to the other, but that’s a minor issue and one I’m happy to tolerate! Thanks for the advice.
The only thing I’ve got to sort now is the leaking tube. There’s a microscopic pinhole in one of the tubes that joins the top of the large boiler, please see the photo attached. It only drips when the lever is raised. Can anyone advise where I might be able to get hold of a 6-8 inch length of the correct tubing?
Thanks again for the help already given - I am feeling much happier!