You're too late! I've done a deal myself for £7,350. And a big thanks to the guys who suggested it would polish up with some T-Cut because it does! The previous owner never, ever washed it so it got badly oxidized, but it scrubs-up nicely with...
Could it be the indicator stalk. The voltage that goes through it and tarnish on the joints fail. I had to do a similar check when main beam failed. Turned out to be a worn out stalk. Dunt the horn run through it?