As well as all ukmicky has set out I'd also suggest you get advice on how to submit a strong objection to the planning application and how to stretch this out. Keep the neighbour distracted while the clock ticks...
The council is completely useless and I did already complain and object to the build.
I asked the council why I have never been given any notice about the build to which the officer replied that it was something along the lines of "certificate of lawfulness" and doesn't require the neighbours to be informed.
The orginal plan submitted to the council and the build that is taking place is totally different in terms of layout, windows etc other than size of the build. I took many photographs during the build and passed it to the planning officer who finally got the enforcement involved. I got a letter by post after more than a month that my complaint has been received and it will be fully investigated.
I called up the enforcement dept to follow up and the first thing the officer told me on the phone that "I should not have received such letter" and then he went on saying that the landlord can build a door or a window as long it doesn't change the dimensions of the property. The officer also told me that "small" changes are acceptable.
During the build the landlord tried to build a big window overlooking my garden (it is not there in the plans submitted to the council) and when I saw that I immediately called the planning officer. The planning officer then immediately called up the landlord and told him his build should be according to the designs. The builder immediately reduced the sze of the window.
Today morning I just went out to monitor what was happening and it seems the landlord is planning to convert the window into a door. The build is taking place at a rapid pace and most of the changes to the plan happened during the Christmas time and also happens during the weekends. I am sure the conversion from the window to door will happen today.