Lupo,
Which ward of Brent Council are you in? The following is just a quick note to say what I would do in your shoes re the council - I am not a councillor btw.
I would echo a pp who said you should go down the route of following the process and how it has not been adhered to.
So a quick google says that Brent council prioritise this sort of case on these grounds (which you will know as you have phoned their OOH line)
- noise that is disturbing many people
- longstanding cases
- cases near to another, in order to maximise visits by minimising time spent travelling.
How long has yours been going on and how many people does it affect? I would have thought that if the council sent a letter 6 mths ago as per your OP then you best bet is longstanding cases.
As a PP says have your diary with dates of noise - and have 2 copies - one to give to someone - one you keep yourself. Also have your diary of when and to whom you reported it.
Speaking/ writing individually to a councillor is a good idea. Some councillors will be better at this kind of thing than others, They aren't MPs (i.e. they do not have secretaries or an office per se) but you can look them all up and get a correspondence address or phone number which I am sure you have done but if not - here - to find your local ward councillors look here democracy.brent.gov.uk/mgMemberIndex.aspx?bcr=1
They will all have better or worse information on a correspondence address or phone number but they will all probably conduct surgeries and worst case you should go to one of those.
Also some councillors even if they are not your ward councillors chair committees - the two most relevant look like (again only a google - I don't know Brent)
Chair of Health and Wellbeing Board
democracy.brent.gov.uk/mgUserInfo.aspx?UID=128
Manages the Council's Housing Stock (according to website) if it is a council owned property
democracy.brent.gov.uk/mgUserInfo.aspx?UID=8874
It may be worth sending a letter to your local ward councillor and copying these two, they may not be relevant but they look the two I would try.
I agree with a pp in that if you have tried everything and have not had response from the council you should write to the chief exec. Give the first people you contact a chance first though.
I would echo a pp though , the nationality of the people in question is not the point. Stick to the facts which affect you.
Sorry this is long and a bit simplistic. I feel for you and just trying to set down what I would do.
All best wishes
DC