Interesting. I've had a similar idea for the US and actually own farmersstand.com (haven't done anything with the domain yet).
I'm not sure people will order local food online in the US, but I think a case can be made for a tablet app that allows the user to sit on their couch and browse local farmers and read about a specific farmer's growing methods, farm photos, selling locations/options, etc. The end goal of the user would be to meet up with the farmer at a market, csa, ect to make a purchase.
Not sure how to monetize or populate it with farmers. Two-sided marketplaces are difficult.