I've never moved a grape vine but I can't see why yhis should be a problem. I would wait until the winter when the vine is dormant though. A 40-year-old vine will probably have quite a lot of roots, but if you dig up as much as you can and get a good root ball it should be ok.

You can cut it back as hard as you need to and retrain it over the next couple of years. This pruning should also be done in the winter as this is the correct time to prume them.

You might also consider propagating some of the canes that you cut off to grow more vines just in case. They root pretty easy.

The roots of a grape vine go down into the ground for miles, so the chance of moving a venerable vine like this are slim. I would take cuttings though, as Myron suggests.

thanks for that guys