Like you've tried to do right at the beginning, your Environmental Health Department will want to try and remedy your neighbour problem informally.
If this hasn't been possible and your Local Authority is satisfied that the noise you're experiencing does constitute a 'statutory nuisance' they are required to serve an Abatement Notice on your neighbour or the person responsible for the source of the noise.
There are different notice requests within an abatement notice and your neighbour or other individual (owner/occupier of a property/business or source of the problem) could be asked to totally stop all noise or they may be restricted to making noise at certain times only (e.g. say only during the daylight hours and not after 11pm).
When an abatement notice is served on a person, they have the right to appeal against this within 21 days of it being initially presented.
If a notice is broken, that has been served on your neighbour fails and without a specific reason or explanation from them, they have committed an offence. In these cases the Magistrates Court can enforce and fine your neighbour up to £5,000 (this is for a neighbour in a 'domestic' home or who has a private vehicle which is the source of the nuisance).
If an abatement notice is broken, Noisy Neighbours can be fined up to £5,000.
ASBO's
ASBO's can be very effective and relevant in your noisy neighbour situation as with noise often comes many different forms of unwanted, intrusive anti-social behaviours.
Neighbours From Hell in Britain have a help sheet about ASBO's and ABC's which you can read to give you a really good overview of what they are and what's available.
More Help and Advice?
Remember: That if you are currently selling your property or plan to in the future, all disputes with your neighbour that have been formally reported and/or acted upon need to be declared to potential or actual buyers (by use of the 'SPIF' - more info on the SPIF is available on the NFHiB Forum). If you don't do this, you could be legally challenged or at worst, sued!
When a dispute has been recorded or put down in writing, or where complaints to an authority (council) have been made, then this needs to be informed to any potential buyers of your property. Ask your solicitor for more information about this.
You can also join the NFHiB forum board. It's very busy and has a lot of good information, we also have thousands of members who understand what you're going through.