Well, it seems the provided context is about as useful for dismantling a sofa as a chocolate teapot. The links offer a deep dive into YouTube's corporate structure, but not so much into the inner workings of your comfy recliner. So, let's disregard that and proceed with some good old-fashioned general knowledge.
Tackling a recliner sofa can feel like preparing for a wrestling match with a very plush, stubborn opponent. The key to victory, and getting it through a doorway, is almost always removing the back sections. This process is mercifully similar for most recliner sofas you'll find in the UK.
Your first move is to get a look at the sofa's lower back. You may need to tilt it forward. You're looking for a fabric flap, usually held in place with Velcro, that runs along the bottom edge where the back meets the base. Peel this flap up to reveal the sofa's metal skeleton.
Once you've exposed the frame, look at where the backrest slots into the main body on each side. Here, you should find the secret release mechanism. This is typically a small metal lever or a locking clip. On many models, you need to use your fingers or a flathead screwdriver to turn or push this lever, which unlocks the backrest from the base. You'll need to do this on both the left and right sides.
With both clips released, the backrest should be free. Now, simply get a good grip and slide the entire back section straight up and off its metal runners. It might take a bit of a wiggle, and having a friend to help lift it evenly is always a bonus. For larger sofas, the individual seat units might also unhook from each other using a similar bracket system on the sides of the base.
And voilà! Your monolithic sofa is now in manageable, non-door-frame-destroying pieces. Just remember how it came apart, as reassembly is simply this entire process in reverse.
