Depends on whether it is a macro or a micro climate:
The length of the growing season of grapes differ from variety to variety and studies shows that at least 170 days of active, frost-free, growing is needed for grape vines to ripen a crop (remember, this figure will not be same for all varieties). But not only the length of the growing season is important; the heat accumulated during the growing season will determine if your grape vine will successfully ripen the grapes or not.
You will have to find out how many days of full sunlight with a temperate above 10°C or 50°F is measured where you live. This is called the GDD or “growing degree days”. Studies made on the physiology of the grape vine, determined that the grape vine is not very active below these temperatures.
The GDD is measured by using the following formula:
(HT + LT) / 2 - 50°F or -10°C=GDD *
HT = highest temp; LT= lowest temp
By adding up all the GDD points, you can measure your regions suitability for growing grapes and should be more than 2000 GDD (Fahrenheit) or 1200 GDD (Celsius) points. The closer your macro climate is to these numbers, the more suitable it will be for growing grapes.
http://www.my-grape-vine.com/blog/grape-growing-climate/
There may be hardy grape varieties available today that were not available uring the Roman Empire.
How does the England climate stack up?