Is that a Stronglight 80 I see on there? Try and avoid throwing money at those cranks, you're better getting a modern 110/74 mm BCD set. I think @doglog might have a set of stronglight cranks with 86mm rings he can pass on, or @6pt may still have some 86mm rings rotting in his shed...?
Hmm. Our middle chainring is quite worn. Will order a new one.
Tandems are money pits. I justify spending on the tandem on the basis that every time I buy something it's basically a gift for my other half.
Not sure she sees it the same way.