UPDATE
Saga have reconsidered their original decision taking the view that as a small scale hobby beekeeper, it was unreasonable to require a significant additional premium for 'business' cover. I am relieved at their common sense and willingness to discuss and tailor insurance to meet our needs. We now have exactly the same insurnace cover for buildings and contents but with the small additional note stating that the insured property is "used in connection with your Honey Producer business and you receive an average of 2 visitors per week". The insurance premium has not been increased.
Despite 'opening a can of worms' etc, I hope that my case may be quoted by others who find themselves in the same position. Clearly at least one major insurance provider is willing to apply common sense and I applaud them for listening and personalising our cover rather than blindly applying inappropriate rules. Please note I have no association or interest in Saga other than as a customer.