Originally Posted by pacenote

As I thought this relates to above ground features but is more applicable to commercial development where these items may be substantial structures, the extracts from your boiler or kitchen would not be included.

On a different note which is totally unrelated to planning issues:
If your proposed extension is with 3 metres of your neighbours house then it would come under the confines of " The party wall act ", this is basically to do with how your new foundations might impact on your neighbours dwelling, if you google it you will find out what is required (usually spending more money on surveyors I'm afraid ).

HTH