http://www.gardenersworld.com/blogs/wildlife/moving-bumblebee-nests/3139.html

Lots of advice here.

I've had a look at the site and its a lovely way to relocate bees. The weather has been so bad this year that there are fears for bees survival so please don't kill them.

Like honey bees, bumble bees 'locate' to a particular nest site, although they don't fly the same distances as the three miles or so of honey bees.
Therefore, you can't just move the nest from one part of your garden to another, as most of the workers will return to the old nest site even though it is no longer there.
But as the website says, you CAN relocate them a reasonable distance away, I'd say at least a mile, as they then re-locate when they see different landmarks when flying from their nest.

If its possible to leave them they wont be there much longer, please be careful, also our bees are in such decline it would be a shame to disturb them. You could ring a local bee man, if you can find one, try yellow pages or something similar. Good luck.

I agree, could yo possibly leave moving that bit of hedge for a little while?