Update:
The landlords/managing agent, were actually more reasonable than I had imagined.
There texts seem pretty abrasive but she said it was on purpose to ensure a prompt reply from myself.
I told them that yes I do have traffic but I wouldn't call it excessive as it's between lunch time and 7pm. And weekdays only.
I told her, when asked about what am I doing, I said no offense but it's not anyone's business, however I'm a business owner, there's no guns or drugs or a weed factory as you can see.
I told her I do take clients here, friends and sometimes daily, that's the reason I'm able to pay annually and live comfortably.
I also showed her all the repairs I done to the flat, she was pleased. Repairs which should have been done before moving in.
I told her that the neighbour has been harassing me, violating my privacy by standing outside my flat door on my landing with another man and interrogating guests. She said that that's wrong and she had told them to not get involved.
She said we haven't had any noise complaints or anything, the only complaint is people coming in.
I told her I wouldn't invite people that pose a risk because then it poses a risk to myself as I sleep there and live there.
As a compromise I said I'm happy to swap flats but I will not change my lifestyle and if you don't want me as a tenant I'll happily leave.
She then said that the neighbours are leaving in about 2 months, so I then said, let me take there flat so my traffic doesn't bother any future neighbours and they were happy with this
They then went to speak to the neighbours downstairs, when they left, the neighbour went nuts and was in and out of the building multiple
Times and just lingering at the door and in the hall way.
Then a couple hours later he installed a cctv outside his landing on the communal stairs.
Now this prompted me to write my first ever complaint in my life. I feel like they are spying on me and violating my privacy and data protection. The neighbour have installed this camera with no consent from other tenants or landlord.
I'm waiting for a reply from the MA/Landlord