Let me throw more light on this:
The man from the council (a surveyor) comes. Now, if I say I'm getting a builder to knock down the wall, I suspect that that would have been the end of the matter. The man, I supect, would say, send in the name of the builder and we will then give you our decision. No talk of surveys or certifications.
Building services I suppose may consider whether the builder exists or not (at least). Anyway, I think building services would put it on the builder to know what he is doing, and by implication, no builder who knows what he is doing removes a load-bearing wall.
I get permission, and when the all is done building services inspects the work.
Okay, but I probably told the man that I was going to knock down the wall. Now that means there can be no reliance on a builder regarding the work. So, the man directs me to bring about a survey and he wants a certification as to the staus of the wall.
So, I reckon it's because I said I want to knock down the wall that I'm in the position that I'm in. But, folks say, it's wrong to ask for certification. That request has been added because I'm doing the work myself.
Let's say I got a builder to knock down the wall for say £50. I bet all I need do is send in the name of the builder and I'd get permission. But, if I don't use a bulder, it will cost me £100 for a survey and certification.