To say tradesman are a bit useless?

Just stick a bit of felt or something similar to where it bangs. No need to buy a new one, just a tiny bit of something soft added

Struggling to see how this is a trade's fault for a poorly designed fan?

Most customers want the cheapest price possible, and if a trade started pricing up the best hardware, he'd soon find himself out of work. Not saying you fall into this category, but I've seen it hundreds of times.

Three or four quotes, all with different prices, as expected, some are widely cheap and I couldn't even supply for the same price, never mind supply and fit. You then start to find out why, when they had a £40 contract tap fitted on a 3k granit worktop when you're called back 6 months later to fit an actual decent tap.

Bit of a sweeping statement there OP!

I have had a few good ones
Many useless ones

We had this issue with the external vent on our bathroom extractor fan. It had three slats and one had fallen off so it would flap in the wind. My husband replaced it with a different design, louvres instead of slats and they are fixed so the wind doesn’t blow them open/close

I think the electricians who did my kitchen (before I bought the flat) must have got the apprentice to do the work. On his first day at work. Unsupervised.

Some are definitely although I've had some fabulous ones down through the years, including a decorator who sanded and varnished my stair railing for free because it would look nicer and a plumber who did absolutely painstaking work, to the extent it got a bit annoying and I wanted him to speed up! His work is still good ten years on. It's best to get recommendations, but that's not always possible. It's the lack of attention to detail that annoys me - doing the bare minimum and not taking any pride in the work.

Sadly, yes, a lot of them are. Since living with a tradie I’m acutely more away of the shoddy jobs, cut corners and lack of care from many tradespeople, as DP points it out to me - from things in my own house to jobs other folk are doing/have done. And you’ve no way of knowing which type of person you’ve got until it’s too late a lot of the time. The other issue is that as a layperson you don’t know the art of the possible, so they can easily fob you off saying something “can’t be done” when it can, they’re just lazy or lack skills.