...I would like to indicate the area of provenance on the label. E.g. "Trumpton Honey" - much in the same way Martha Kearney labelled hers as "Barton Grange Honey" (in spite of the OSR content, which was clearly from further afield).
Regulations state that - in respect of regional, territorial or topographical origin, this is OK, as long as the honey comes ENTIRELY from the indicated source...
The rules are in "The Honey (England) Regulations 2003"
http://www.legislation.gov.uk/uksi/2003/2243/made Minor amendments from 2005 and 2007 don't change the geographic requirements. The legislation and the DEFRA "Guidance Notes" to the Honey Regulations (2003)
http://multimedia.food.gov.uk/multimedia/pdfs/honeyguidance.pdf both also refer to the "Food Labelling Regulations 1996"
http://www.legislation.gov.uk/uksi/1996/1499/contents/made This applies to the the packer more than than the producer and is where the packer's contact address etc are covered. The Guidance Notes come with a warning that legal interpretation is for the courts, but they are a pretty good basis for your reading of the statutes if Trading Standards question what you have on the label. As devolved legislation the links are English; there are equivalents elsewhere.
As 4.1(ii) on page 12 of the notes says, the country is mandatory, but not defined. Not very helpful. In practice country could be, but is not always the equivalent of EU member state. As it suggests, "Produce of England" or "Produce of UK" would be fine but you'd have a hard time justifying Trumptonshire as a "country".
If you want to have a narrower geographical range, that's in 4.3 "Optional labelling information" on page 14.
(ii) Regional, territorial or topographical origin: provided that the honey comes entirely from the indicated source.
Which doesn't really help when bees range over political boundaries. The established practice of adding a county, as seen on many bought in labels, only seems to be covered in the written advice that says it also needs a country in 4.1 -
Therefore honey that is harvested in Wiltshire could include a statement such as “Wiltshire Honey” on the label.
That would argue that the "harvest" is the relevant factor. I would suggest "harvest" is basically the hive position; taking supers from Wiltshire to Norfolk to extract doesn't make "Norfolk Honey". It is probably within the general provision of not attempting to "mislead", as used in the references to country. If your hives are all in Trumpton, then "Trumpton Honey" is justified, even if they visit the OSR at Chigley. Just as I would think that "Barton Grange Honey" would mean the hives are at Barton Grange but obviously the bees go further than the
four acres they sit on and the extraction could be a few miles away. If you
move the hives to the OSR at Chigley, then you might be better using "Trumptonshire". BTW Gordon Murray said in an interview Chigley, Trumpton and Camberwick Green are in an equilateral triangle, 1.5 miles apart from each other.
The question of how you could use labels based on region, territory, topography or even ancient geography or fiction is left open. For instance East Anglia, Wessex, Chilterns, Jurassic Coast or Herriot country. Again, the basic test is probably the intention to deceive. If it's not a current political boundary you might need some references from bodies such as the local tourist office to back up your answer to Trading Standards.