One for the suspension experts maybe. I have an MX5 as road/ occasional track car. 67k miles, Mot pass last week. Car is fitted with Meister R coil overs - 5k miles old. In the last week it has developed a random but ever more frequent front corner knock which is excited by both 'smooth' and rough roads, but inconsistently. It can occur at near walking pace and at speed. Everything appears good and tight, steering is smooth and linear - no knocking. Had the car out at Cadwell yesterday, no adverse handling or braking effects. What could it be? A possible internal shock failure occurred to me ( loose rebound bump stop?) but that surely is unlikely. I plan to swap right and left to see what that does but before going to all that hassle are there other things I should check first? Another possibility that has been suggested is a 'loose' brake pad. I changed the discs last week and it went back together fine including anti rattle springs and anti squeal shims. I am not sure how a brake pad could be' loose' but it is something that has been changed. Brake performance is fully up to snuff on track and road. I think I might take it apart again and reassemble just to be sure. It is easier than a suspension swap so I will give it a go. I have done it all before so I am confident in this undertaking. Any other suggestions gratefully received.

More than likely an anti roll bar link worn

As above 9/10 It's a drop link.

I had a knocking noise on my NC, this was due to worn sliders in the calipers (some body had used the wrong grease to cause them to wear) so this might be worth a place to have a look at.

Another vote for ARB links being the first thing to check.
We had a Zafira as a family car for years. It developed a knock, quickly sounded like it would copletely fall aprt. £20 for new ARB links and sorted. The old ones had a tiny bit of play.... and I mean tiny.

My wife's NC was the same and new anti roll bar links sorted it

Thanks for the inputs. I had not thought of drop links. I have a Hard Dog uprated bar so loads higher than standard I imagine. Don't know if the drop links are standard or not. Anyone know? I will ask on Nutz as well.

ARB links are easy enough to check at home and cheap and simple to replace at home as well. Just replaced the front ones on SWMBOs VW Touran as a rubber boot had failed on one of the joints and it was knocking (came up as an MoT advisory). A pair of ARB drop links were £30 and 1/2 hours work with a jack and spanner to remove the old and fit the new. Knock gone! If you've got a stiffer anti-roll bar the ARB joints will be under more load, so more prone to wear.

Fairly sure Hard Dog refers to the roll bar, as in stops your head getting squashed if you end up upside down.

Anti roll bar is the suspension component.

As said, it'll be a drop link failed.