Boot's on the other foot...

[MadDogMcQ]

You're right Mike - it is the carb-to-airbox connector. In fact, reading through the mechanic's email again, he does actually say it's that. He's just asking do I want it changing because it's kinked and damaged - it's only £6.
My bad  :rolleyes

However, as you suggest, a small air leak there won't make a blind bit of difference! He isn't doing a full monty - just the slip-on mod. He said the mod to the carbs was very easy and I passed him high-quality printouts of all the online instructions and even bought a good pin-vise to make sure he wasn't tempted to 'bypass' the bypass drilling  :lol

This guy tunes Gixers and Blades to very high levels and his work has been featured a few times in Performance Bikes magazine. I'm sure it'll all be fine 

Tom