Home extension scope of works - mis-sold and breach of contract

[Bluezdep]

I've had an extension built at my property where I signed a contract with an appendix listing the scope of works and also the items I would have installed by the contractors who also placed the orders.

Part of the items are for 'ABC' bi-fold doors to be provided by their suppliers. I was happy with the selection and the specification following research online as well as the technical details, especially with the bi-fold doors as they came as 'PAS24 certified' (enhanced security) as standard, and so I didn't question the security of the doors.

The bi-fold doors arrived on site last week and installed a few days ago, however, when looking at the instruction pamphlet during the installation by the contractors, I noticed that the doors were not the ABC manufacturer and instead by another company named 'XYZ' which isn't what was agreed to before the work started a few months back. So I contacted them and stated that the doors aren't what I was expecting based on the specification and that they would need to be replaced.

I've spoken to the contractor and these are the unfolding events thus far:

1. The building contractor was adamant to begin with that the doors are ABC. I mean this is an insult to my intelligence on the logo of the door handles plus the pamphlet inside the box. One of the builders even received a call from their office asking how I found out about the doors!
2. Eventually, they then said that the XYZ supplier manufacture ABC doors although I spoke to XYZ to ask about the doors and the PAS24 security. They confirmed that they only provide the ABC profile but if I wanted PAS24 certified doors then it's an added option - extra cost.
3. I explained this to the building contractor where they are now suggesting I didn't request for PAS24 doors, but I didn't have to as the ABC doors have it as standard. Contractor denies this even though the ABC manufacturer website states it comes as standard, hence I didn't need to request anything.
4. After a heated discussion, the contractor said they would contact the XYZ manufacturer and see what they can provide as a solution.
5. The solution being provided is that the cylinder lock needs to be changed to make it PAS24 but this I'm not entirely convinced on.

My concerns are:

• Being mis-sold and the contractor not abiding by the agreed scope of works - breach of contract
• Doors not as per the technical specification with PAS24 enhanced security and unaware if just a replacement cylinder lock makes it PAS24 or if the whole mechanism needs to be certified
• Home insurance potentially not paying out in the event of a break-in if stating that there is enhanced security when taking out insurance and then the underwriters surveyors report shows that the security was substandard.

I know that these guys are trying to take me for a ride but I'm not taking it. It's like wanting to buy a Samsung TV with OLED and receiving a Bush LCD TV, or buying a car where the dealership tells you that it has an immobiliser and you later find out that it didn't after the car is stolen and the insurers don't pay out.

It would be great to receive some feedback and guidance on the above, and what steps I should take even if it has to be through litigation. In the meantime, I'll be seeking written confirmation from both the XYZ and ABC manufacturers of the PAS24 specification in the event I need to build the case further with evidence.

The contractors were great until four weeks ago, but there have been a number of issues which they've swept to the side and communication has been poor from their side. My biggest concern is that they won't complete the job nor clear up their mess if I instigate litigation.

TIA