I'm almost certain that you can forget about the possibility of needing to specifically mention the programme on your insurance policy. I've done a bit of buying and selling at auctions over the years, including a fair amount of 'printed ephemera'. Depending upon the auction (and whether there are rival bidders with a common interest present), a programme like the one you describe could sell from anything between �2 and (at the very most) �30.
If you want confirmation of those figures, I suggest phoning or e-mailing a dealer who specialises in printed ephemera and stating that you collect documents relating to agricultural shows. Simply ask if he has anything similar in stock and seek some guideline prices from him. I know that might not seem entirely ethical but I've provided one of the UK's leading dealers (Ken Graham) with plenty of trade (by recommending him on AB and elsewhere), so I don't feel too guilty about suggesting that you should seek a price from him:
http://www.kens.co.uk/
(My guess is that he'll offer �1 to �5 if you're selling and quote �10 to �50 if you're buying. The printed ephemera business needs to operate with such large mark-ups because of the slow turn-over of items).
Chris