Thank you Gasman! I can't wait to tell a new customer that a failed thermocouple has turned into a boiler replacement!
If you tell them nicely you will earn well from a nice boiler swap if they take it well. If they don't take it well, someone else will get the job lol. Or more than likely someone will come along and bodge the boiler back together with a rope seal and make you look like the bad guy.