"Yields are relatively low here," Dr Richard Smart of consultancy Smart Viticulture said.
"The UK is cold, particularly in spring, which pushes growth back, and then there is also the risk of frost. It also has too much wind and rain - you want around 600mm a year."
This causes too much vegetative growth at the expense of ripening, and also encourages mildew and Botrytis, he pointed out, adding: "I wouldn't encourage you to do it organically or biodynamically in the UK - don't make it any harder on yourself."
He also urged: "If your site's at all windy you need to plant windbreaks, of which the cheapest and most effective are trees."
Meanwhile, a clear protective film format from Capatex, being demonstrated at the Kent show, could serve as "an insurance policy against the elements", he said, but added: "You need an extra tonne per acre to cover the cost of it."
Tourism, he added, can tide growers through a bad year, "so proximity to a main road should be part of your site selection".
He said: "If you are small and new, pay someone else to make your wine, at least for the first few years. So many people screw it up and end up with wine they can't sell."
But a larger UK industry could overcome these issues of scale, he pointed out, and would be better able to build up a research base. "You are competing against countries with many generations of experience," he said.