Einhell 2342167 TC-VC 1820 S Wet And Dry Vacuum Cleaner, 1250W, 20L Stainless Steel Tank £42 @ Amazon

Have one. Suction is okay.
Tools are a bit stingy with just a nozzle and floor unit. No brush. Host diameter is 36mm AFAIR which is good for not getting things stuck inside, but poor for compatibility with any other vacuum tools you might have. Power tool attachment tend to be tapered so most do fit.
Very top heavy too so tends to fall over easily. Being a wet and dry it has a floating valve to protect the motor, when it falls over that triggers so you have to totally turn it off and wait. (edited)

Oh no. I'd hate to have to remember to switch on the vacuum This is better in my experience than the similar priced Titan wet n dry from Screwfix which iirc has basically a socket where you plug in the appropriate power tool - so on means on. Or you know, just press one extra socket switch on. Horses for courses. This Einhell really sucks - in a good way

It comes with 1 bag, and one wet filter thing. Highly recommend getting HEPA bags - most generics will fit. I've had good success with this 5 pack at £11.49 titan-pro.co.uk/p/4…ags

Yes agreed it's difficult however airwatts is the true figure eg you could have a high watt motor but due to the seals ( depending on brand) it may leak air ending up on a lower air watt than a comparable lower motor competitor

Hell of a lot cheaper than the £400 dust extractors. Alternatively, you can use a Henry Hoover

Yep, correct

Its fine (so far)! Big button. Simple on and off.

Hoovering up things that are wet?

That can be anything from cleaning spills on the carpet, shampooing your car mats and hoovering the solution off, or cleaning up a bowl of coco pops you just dropped.

I'd have thought it would work alright for shampooing a sofa. I think its design and the fact that it's made by Einhell makes its marketing more "aimed" at a workshop, but there's no reason you couldn't use it at home.