Planning can be refused if enough valid objections are made. Have a look at this list and use it for yiur letter. Many things that concern you will not come under planning. A although a worry, dust and noise from the building works for example will not be grounds to refuse as the builders can be told to keep those to a minimum and they are short term.
This list is the type of thing that will be taken into account.
• Adverse effect on the residential amenity of neighbours, by reason of (among other factors) noise*, disturbance*, overlooking, loss of privacy, overshadowing, etc. [*but note that this does not include noise or disturbance arising from the actual execution of the works, which will not be taken into account]
• Unacceptably high density / overdevelopment of the site, especially if it involves loss of garden land or the open aspect of the neighbourhood (so-called ‘garden grabbing’)
• Visual impact of the development
• Effect of the development on the character of the neighbourhood
• Design (including bulk and massing, detailing and materials, if these form part of the application)
• The proposed development is over-bearing, out-of-scale or out of character in terms of its appearance compared with existing development in the vicinity
• The loss of existing views from neighbouring properties would adversely affect the residential amenity of neighbouring owners
• [If in a Conservation Area, adverse effect of the development on the character and appearance of the Conservation Area]
• [If near a Listed Building, adverse effect of the development on the setting of the Listed Building.]
• The development would adversely affect highway safety or the convenience of road users [but only if there is technical evidence to back up such a claim].