This site we found recently, British Listed Buildings, is a really good tool for checking, the accurate status of the listing for your building.
The listing covers England, Scotland and wales, and the excellent search engine is realy good at finding a building just by Post Code.
We have used it several times recently, and found it to be a great help.
For further reading on Listed buildings, try this Wiki site, the reading list at the end is also worth following up.
The photo today is of a classic window timber shutter detail to a stately home I visited this summer.
You might also want to read up on producing a Heritage Statement, and a complimentary D & A statement.