Hello. I am a solicitor with over 15 years experience. I will try to help you with this.
Has the work started yet and have you discussed your concerns with you neighbour? I am guessing that there was no planning permission application made.
I am afraid that as far as light in your garden is concerned there is no right to light. If the light into your house is affected then you may be able to seek compensation and in extreme cases an injunction to prevent it being built. Is there any particular reason you fear that there be noise associated with the home office.