On Wed, 20 Jan 2016 11:11:13 +0000, Adrian wrote:

I've just ordered some from a random 'bay seller - they use the terms
"u-clip, speed clip, chimney nut, motorcycle fairing clip" in their
description alone.

Any of those should find a source - I'll let you know what the quality
of these is like when they get here. 25 x M8 for £9 delivered.

Well, they've arrived, and they look just fine. Semi-bright finish as
shown, not yellow passivated or black.

http://www.ebay.co.uk/itm/321969313302