If spoken to tenant above about the noise with no improvement, I'd google similar issues within council tenancies, but also private occurances. See what successes other complainants in similar situations have had and how they tackled this dilemma. Notwithstanding the above, it was IMO a mistake to advise the council that the situation was resolved when it was not. I would raise again, by letter, with council as a noise issue and be clear about impact on you as a tenant. Do the leases on these flats allow tenants to sand their floors ? My final (though a negative) and last response would be to tell council the property is being let with as much evidence as I could muster. It's a shit situation and I think whilst checking other's experiences you should also try again patiently to discuss with tenant upstairs including letters (you keep copies) to evidence the efforts you have made, before moving onto further action.