I can only speak for my own area.
Our local power supplier Scottish Hydro Electric, now known as Scottish & Southern Energy for the power distribution side, have a 4 page form you are required to fill in.
In this form you have to provide installation loading details, number of rooms & any special power requirements, eg. machinery, lifts, heating etc.
If you require a new supply for a new building you also have to include site plans.
Details of the electrical contractor have also got to be provided. Since earlier this year there is a requirement for the electrical contractor to be SELECT / ECA or NICEIC registered, otherwise there is a £40 fee for checking the wiring, with additional fees if it is unsatisfactory 1st time.
Registered contractors, like myself, self certify & connect to the meter or isolator ourselves.
All new single phase supplies in this area utilize meters with an integral isolator switch, which allow contractors access to the load terminals of the meter.

NICEIC = National Inspection Council for Electrical Installation Contracting.
SELECT = Electrical Contractors' Association of Scotland.
ECA = Electrical Contractors' Association (England, Wales & N. Ireland)

I have a copy of the Application for Electricity Connection, which I will try to get posted, it is however a year old & outdated.