Hi zarafc - I can't help you with the pruning because I've never grown a vine. Forgive me if you know this, but whereas to me, and possibly you, a 'vine' means a grape plant, this is a mainly US Forum where 'vine' means any climbing or scrambling plant. So if you don't get an answer here there is a Fruit and Orchards Forum on GW which has some experienced grape growers on it. Meanwhile:

Here is a link that might be useful: Grape pruning

Hello floral_uk - I didnt know and thanks for the info. I will look at the other forum