In recent years complaints about noise and disturbance from fireworks have increased dramatically.
There are now specific UK regulations to cover noise from fireworks and if you are disturbed and wish to have action taken, it is a matter of trying to get the police to take action under the Regulations, or of pressing into service the normal statutory nuisance legislation. The regulations broadly prohibit nighttime [23:00 to 07:00 hours] fireworks except for New Year [Chinese & Western], November 5th and Diwali. So if November 5th was on a Thursday and you wanted to hold the party on Saturday [the 7th],it would appear that nighttime fireworks would not be permitted. Fireworks before 11pm do not appear to be prohibited under the Regs.
If you are trying to use nuisance legislation, it is probably unlikely that a Court would accept that a single firework party was a nuisance, unless possibly it disturbed most of a night's sleep [23:00 - 07:00 hours], but it may be possible to prove that regular events at the same venue, are a nuisance; it may even be possible to get a Court to accept that collective events in an area are a nuisance; the biggest problem being finding the person responsible for each firework event [or the land owner] so that they can be enjoined in an action.
Probably the most relevant assessment methodology is the WHO guidance with regard to instantaneous loud noises at night.
If you are considering having fireworks at an event and are concerned about disturbing neighbours, a reasonable starting point would be to avoid the noise night unless it is New Years Eve!, try and keep it short and as early in the evening as possible; if you think that disturbance is inevitable, it is also a good idea to forewarn residents by means of a note through the door, to tell them the start and end times and stick to them.
The Noise Abatement Society has a forum on fireworks noise here.
Hope these sparse comments help.