The best time to move clematis is in the early spring, before major growth begins. You could easily lose them if you move them when they are this tall. You could try pruning them back to 6-12" and then move them, however, (and this is my own opinion), you lost your best chance for success by waiting too long.
Suzy

You should have moved them earlier while they had hardly any growth on them. But if they must be moved you will need to get the biggest rootball you can dig & move. The more of the rootball you get to the new spot the better the chance you have for them to take in their new spot. 5 year old plants are not the best size to take. Usually if you can move younger plants there is no problem. When you plant them in the new spot make sure to get the top of the rootball at least 2" deep than it sits in the ground now. Always plant a moved clematis 2" deeper than it sits in its current spot. Keep them watered good & give them Rose or Tomato food. Good Luck

Hi brightmoregirl,you should have no problem moving your clems.The only bummer is that it will set you back a year on the flowering.I would do just as mamoo said be sure to get as much of the rootball as you can and have the new hole all ready to go.Clematis are tough plants when they get past the first couple years so they should be fine.I removed some Huldines when I worked at chalk hill and the rootballs were so big I had to use a small backhoe to dig them up after I dug them up I let them sit there outside thier holes roots showing and no water.A few stayed like that for a couple weeks before I chopped the roots off and potted them up in 5 gal pots.All did fine and were sold as nice plants.