Some quite interesting replies to the OP.
Firstly Noise Nuisance doesn't fall into the remit of the Police. As someone has already posted it falls to your local council using an Environmental Health Officer to enforce the Noise legislation.
In some large Cities these Officers regularly patrol at night and can call on the the backup of Police Officers to ensure breaches of the Peace or any other offences are not committed against them whilst they carry out their job.
Police Officers are sometimes called to these types of incident but it really boils down to how busy they are. Normal practice is to refer the complainant to the Environmental Health Department - who will take on board the complaint - they'll probably not do a lot if it is a one off, but if it is persistent ie night after night or every Friday evening, they will take action.
In most cases the complainant is asked to keep a written diary of the times and duration of the noise. The Environmental Health Officers can also fit recording equipment in the complainants house to record the noise (usually automatically records when the noise hits a certain level). All of this can result in a Court appearance.
As for Police Officers arresting someone for a Breach of the peace for playing loud music - no they will not - a breach of the peace is committed only when an individual causes harm, or appears likely to cause harm, to persons or in their presence their property, or acts in a manner the natural consequence of which would be to provoke violence in others.
As for powers of entry - indeed all Police Powers in the UK - take a look at the following it details what Police Officers can do legally in the UK.
Police Powers in England and Wales