Mos Bare Bones

[MargoTester]

2d fellow is about to go wrong with rotter - it's a fair matter (two words, 11letters)
8d choose to reply unwisely on something that can broken easily -11 letters
9a all encompassing Londoner Elliot's written about (three words)
Struggling today thanks for any help

[Lie-in King]

2d Ferris wheel - 'f(ellow)' + 'is' (about) 'err' + 'w(ith)' + 'heel'
8d Electrolyte - 'elect' (choose) + anag 'to rely'
9a Rolled into one - anag 'Londoner Eliot'

[Oldred]

2d ferris wheel

[MargoTester]

Thank you very much ,once again, lie-in-king

[Lie-in King]

You're welcome :-)

[MargoTester]

Thanks also to oldred