Gents, thanks for replies. As Tom says, I have to turn them to sidelights for work reasons (can't be dazzling the pilots, can we!).
I suspected it would be a Tech job so off I will go to get Tech programming.
As I had to get jump started again this morning, I suspect the battery now needs replacing too. Oh well, as it's a GM battery it's probably the original from new (although that would make it at least 10 years old).