Replaced Windows/Doors no paperwork

[Buildingregret]

I've really messed up I think
I've had an old UPVC external window and door replaced. As I wanted them a specific style I commissioned them to be made by a local carpenter/joiner out of hardwood.

All paid, the windows/door themselves look good but the fit isn't great.

I've really noticed that the room is so much colder, and I've just realised that I haven't had the paperwork from the fitter to say the work meets building regs.

I did state in emails that thermal properties were important to me and that I wanted 24mm minimum double glazing before getting the final quote.

I feel so stupid, I'm not sure the window/doors are fit for purpose. They cost several thousand £ and are the first thing I've ever done to my house and I'm so upset I've messed it up and been ripped off.

What can I do?
I've now discovered the joiner isn't register with FENSA.
I know it's my responsibility to sort this mess out, but I have no idea someone would make windows/doors for a living that wouldn't comply with the minimum standards.
They say they have never been asked before.

Don't worry too much yet. They may not be FENSA registered, but Certass registered instead; try asking that. They're both ultimately the same thing.

I doubt it, he would have told me when he told me he wasn't registered with FENSA?
I can check with him though.

He may have done, or may have perhaps assumed that you knew.

Even if he's not registered with either of them though, there's still a solution which is to get the local council to come out and provide building control approval. Your council's planning team are usually the ones who will help with this. There is a charge involved which I think varies from council to council.

I know this doesn't solve the issue of the room feeling colder which you'd probably have to get the joiner to come and resolve, but hopefully it will give you some comfort that you've at least got options to get the paperwork sorted.