You can find your DNO here.
http://www2.nationalgrid.com/uk/Our-company/electricity/Distribution-Network-Operator-Companies/
You may need to look carefully as I believe that Lincolnshire is covered by two DNOs, it will depend on your exact location..
EDIT Western Power have a handy search facility that will tell you who your DNO is.
http://www.westernpower.co.uk/About-us/Our-Business/Distribution-area/Find-your-distributor.aspx
http://www2.nationalgrid.com/uk/Our-company/electricity/Distribution-Network-Operator-Companies/
You may need to look carefully as I believe that Lincolnshire is covered by two DNOs, it will depend on your exact location..
EDIT Western Power have a handy search facility that will tell you who your DNO is.
http://www.westernpower.co.uk/About-us/Our-Business/Distribution-area/Find-your-distributor.aspx