Wall removal consent / built to code

Hi, i have a wall that was removed without consent. Builder said the beam needs to be bigger than what they added.

I told my bank there was no consent and they advised to get consent when I can kind of thing.

Builder said he can fix the wall and as a LBP write a memorandum to state the wall removal has been built to code and save the cost of council.

Re-do beam and plaster = 3k

Council consent = 3k (very approx cost)

So for half the price I get the wall fixed but don't get consent but have a letter to give future buyers etc.

What do you guys think? I feel I have to go all out but 6k is so expensive. Maybe I need more quotes.