Thank you for all of your reassuring comments & fast replies.
Day 2 of Aero ownership brings sunshine & an empty car park to check out that reserve gear properly.
It does seem fine when the clutch is fully engaged, the issue being confined to clutch engagement/disengagement, & a more gentle & deliberate approach reduces the noise further. I can therefore only think it is down to the unforgiving nature of the drivetrain, although I had not noticed any issues in the forward gears.
Phew, panic over
