Table/Eating Grapes

Last year, the kids (with help from me) built hubby a lovely gazebo type thing to hang his hammock in, and with grapes planted on each side to trail up over the roof of it. Over the winter, we moved house, and as the grapes were part of a father's day gift, I thought I'd try and move those too. Well, surprise surprise, they survived very well, and now have set bunches of grapes on them. Not bad for uprooting on Boxing Day, sitting in bags for about a month before finally getting around to getting them in the ground - albeit a frozen ground!
I've never grown grapes here before - and as the grapes at the moment are, on average, about half a centimetre in diameter - is there anything special I should be doing to ensure we actually do get to eat some ripe grapes this year?

I've noticed the ones for sale in the nurseries at the moment have larger grapes on them than ours - possibly due to being a different variety, but they seem so much further ahead. I'm thinking of building a 'casing' around them that I can slide greenhouse glass into in the early spring to get them going quicker, and then slide out to remove as the weather warms up.

Any experienced (and successful!) grape growers with any useful advice? Much appreciated