J Pearce

As well as the atterotech mentioned upthread, there’s also the Audac WP225 unit. It’s a wall plate with bluetooth, line, and mic with balanced stereo audio out. Just needs some DC power.

Canford have various available, including 400mm. The keyword to search there is "gooseneck microphone". Be aware that a longer mic will place extra strain on the panel mount XLR - this could lead to faster wearing.

If it’s an install and you want compact, how about unistrut rather an a bar? Powder coated if you fancy a smarter finish.

Use a HDMI audio de-embedder at the stage end before it hits the HDBT link? Cable it up with the lectern mic etc.

How boring. EV's weren't unreasonably priced at £149 each.

We had similar with an EV amp module. It worked out cheaper (and quicker!) to swap the module than it would have to pay for diagnosis and repair.

Ah yes, Temu, that well known provider of solidly tested and rated rigging equipment...

I would recommend Doughty Supaclamps too - and they have the advantage of clamping to various sizes and shapes. They do a M10 stud that locks into the clamp to provide solid rotational locking.

Canford also stock some options

To be fair, most of the available systems use 1.9GHz or 2.4GHz - there's so few other bands that are available across all territories.

Have you got the sample rate set correctly? A 48 vs 96 sample rate mismatch can sometimes show up as L/R issues.

You're probably better off with something from the used market. £300 might just get you a 10deg or 14deg 750W S4, an iris, a stand, and a single channel dimmer. I doubt you'll get anything you want to own in a new LED spot for £300. Or look out for a used RJ Buxie or similar - good spots that with care should last years, but I'd expect to be paying around £1200 a unit really.

If you're dealing with a zoned system then it's worth looking at Cloud Electronics - it's their speciality. They have multichannel rack amps, which are designed to sit forgotten about in a hidden rack and just keep doing their thing. The amps have no controls on the front so can't be fiddled with. The amps use phoenix connectors rather than Neutrik, which can also help keep costs down.

They're not top-end doughty clamps, but equally you're not daily-touring them or using them on massively heavy units. You're buying them from a registered UK company, not a dodgy ebay importer - so in the unlikely event of a lawsuit would have some defence back to the supplier. Be aware of over-tightening, as this can cause cracks in the upper portion of the clamp or the riveted pins to fail (but you'd no doubt spot the beginnings in your periodic inspection of rigging accessories) - no wingnut spanners on these. If you wanted a half-way point between the cheap stuff and Doughty stuff, the Global Truss bits are pretty good. Avoid Doughty's Twenty Clamp - horrid things. They're ok-ish brand new, but over time they crack, they don't tighten properly, they chew up the bar, they're not rated for vertical rigging - just harbingers of doom and misery. They don't really offer anything a much cheaper hookclamp doesn't.

Metal is not cheap, time is not cheap, workshop rent is not cheap, power to run the machines is not cheap. Probably not worth pricing jobs much below £50 really.