when i got my allotment from the previous people they had 3 large rosemary plants growing on the edges of what i wanted to make a border, it was in the middle of september & i needed to organise the land, me & hubby dug them out (tried to get all the roots in with them) replanted them with some compost and loads of watering, at first they seemed to be going downhill but after keeping them very well watered they are still doing beautifully, and that was 5 years ago! sorry, can't help with the bay as mine's in a big pot, but i reckon you should be allright moving the rosemary, good luck :-)