moving established rose

I Have 3 established rose bushe's that I reluctantly have to move, what is the best time of the year to do this? and what would be the best way to do this

The best time is just now really. Prepare their new hole and add a bit of bone meal or some hearty organic matter roses thrive in hearty full soil. Dig around the rose forming a nice solid root ball about the width of the network of branches. Give them a nice open space and try and avoid planting them where roses have been before  to reduce the chance of disease. Be careful not to plant too deep, try and re-home as it was before so the flare of the plant is sitting at the same level. When the weather warms up a bit or if there is no chance of frost between now and say march give them a good prune for example reduce the growth by a third, you need to be careful of frost when pruning to avoid damage to new delicate growth. Hope that helps, good luck.

When they are dormant. The bare rooted roses you buy from November onwards were growing in fields days before they was dug up and sold to you, so anytime between November and Easter as long as the ground isn't frozen or waterlogged.