This is from Westminster Council's website:
Householders working alone or with limited help often have far less time to carry out home improvements than a paid contractor and the team recognises this. Generally, it is acceptable for householders to undertake DIY work between the following hours:
Generally speaking 3-4 hours total duration, each day between
* Monday to Saturday : 8am-9pm
* Sundays and Bank holidays: 10am-4pm
However, the Noise Team will consider each case on its merits when considering how to tackle DIY noise complaints and will take account of factors such as the equipment used, and the overall duration of the job.
Larger DIY projects requiring more time to complete than allowed in this policy will need to be carried out during normal Building Site allowed hours:
* Monday to Friday: 8am - 6pm
* Saturday: 8am - 1pm
* Sundays and Bank Holidays ? No noisy works
It is also advisable to let your neighbours know when you are about to carry out noisy work.
Your own local authority may have different guidelines and you're best advised to check their website.
Personally, if I had to live next door to building noise all day and evening for 1 week, let alone 3 months, I'd be incandescent with rage to a point where I wouldn't be responsible for my actions.