Moving large/old woody shrubs

Hello

I have a decent sized old Hydrangea that I would like to move to the back garden to allow it the space it needs to spread out.
The change in location would get a more sun but also more wind from the south and east but would be protected from the north and west. It would also be rain shaded due to a north wall.

In what situation can you not dig something like this out? I'm concerned the root system might be all over the place due to very shallow soil.
What month would be best, I'm in north Scotland and everything is starting to die back

There are some other things I would like to move too as that area of the garden is just not very good for things like this as I would prefer it to grow out rather than have to keep cutting it back massively every winter

Cheers

 

I think the hydrangea would be better not in rain shadow.

The general advice for moving large old shrubs is to dig a trench around it, cutting through whatever roots you need to, backfill with compost and let it re-grow fine feeder roots, then move it the following year (at which point you'd probably need to cut through any roots going deeply down underneath the shrub).

Tree and shrubs: moving plants / RHS

 

If you're having to cut it back it's obviously in the right place, and happy. I don't have experience of growing in Scotland, but generally, Hydrangeas like shade and moisture. The proposed spot doesn't sound ideal. As it's recommended to prune them annually anyway, I'd leave it where it is!
As for the other stuff that you want to move, Googling each plant to find out what sort of root system it's got would be a start. Some plants like Rhododendrons and Camellias have a compact, shallow rootball and move easily, but tap-rooted shrubs wouldn't take kindly to change.