Demolition date

[jbml]

Well, I considered it to be "adding something" to draw attention to the different ways in which legislation may have been amended, and to the fact that electronic publications may not give you the version of the text that you are looking for but that this may not always be clear, for the benefit of those whose skills and experience lie in different fields than legal research.

If anybody else chooses to characterise this as "sniping from the long grass", then we will just have to agree to differ on that one.

[aghadowey]

Back to the original query 

Planning office would certainly be my first place to check (although they may or may not hold paperwork from 1970s).
Next I would try local library, archives, newspaper office(s)- if you are lucky they will have a filing system for old stories, historical society.

Good luck

[Thornwood]

Thanks '  adhadowey', I think we better call it a day on this query. It seems that my original question has many answers. The demolition was not part of planning permission for something else. The land was leased and has reverted to a field where horses graze. Newspapers have drawn a blank and so have locals so will contact the planning office this week. Can't contact local history group for information as I am a member and this building is part of the research we are doing.
Again thanks for all the suggestions, far more than I ever expected.
Thornwood.