Planning
Below are some useful links to help you with the planning of your basement conversion.
Planning & Building Regulations
https://www.planningportal.co.uk/info/200130/common_projects/5/basements
Planning in Your Area
Barnsley: Barnsley Council Planning and Building Control
Chesterfield: Chesterfield Council Planning & Building Control
Derby: Derby Council Planning Applications
Doncaster: http://www.doncaster.gov.uk/services/planning
Nottingham: Nottingham Council Planning & Building Control