Why not have the rendering work done at the end of the growing season in say October, when the hebes will be safer to move to a temporary bed, and you can replant them next spring.
In my experience, builders don't seem to know the difference between weeds and garden plants and certainly just throw rubble all over the plants which are 'in their way'.
Trying to move them now in mid summer will almost certainly harm them unless you can remove them with lots of root and keep them very wet; but even so, you will damage the fine root system.

As very few builders seem to be gardeners or appreciate plants then it will be up to you to protect them, Ww! I would not 'want' to move them but accept that they may have to be to protect them from being trampled. Can you rig up some sort of support with boards above the hebes? It would have to be strong as the builders will use it to stand on, of course!

I suppose it depends on the size of them and how much rendering is being done and if the plants could interfere with a good job being completed by the builders . If so it sounds like it would be best to dig them out and save them. Not ideal maybe but it may be best in the end.