As someone who's had to live above and below a succession of noisy neighbours, I do sympathise. Get Lewisham Council on board and keep a log of incidents - it does help if you can produce a list of noisy episodes with dates and times.

Bear in mind that Lewisham noise teams go home at midnight Monday to Thursday and the police don't want to know unless it becomes a public nuisance - ie a disturbance that spills out onto the street. But there is action you can take through the council and your leaseholder/management company if you have one.

I really felt powerless at times when it was happening to me but the management company of my block are now taking it much more seriously. Remember the noise makers could be in breach of their leasehold and tenancy agreement too. Good luck with it and hope it's resolved soon.