Salvia greggii and Clem Daniel Deronda

It's two queries really:
1. My Clematis Daniel Deronda is not happy where he is - I think the problem is down to the soil needing lots more organic matter dug in. I plan to dig Daniel up, cut him hard back and put him in a large tomato pot with lots of good soil and compost and give him a bit of tlc and get him growing strongly while I improve the soil by his trellis before moving him back at a later date. When shall I dig him up?
2.. In front of Daniel is a very happy Salvia greggii - it's been there for two or three years and is the size of a wheelbarrow and blooms its socks off. In order to improve the soil for Daniel I really need to enlarge that bed and move the Salvia forwards into the new bit. What's the best time of year to do this?
So really, how would you plan the entire operation?
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Posts
Dove.
Agree about the Clematis. I would pot it up in Autumn.
As for Salvia, I would probably move it when it starts into growth next Spring.
You could then re plant both at same time.
When you don't even know who's in the team
S.Yorkshire/Derbyshire border
Take cuttings of the salvia now. Any non flowering shoot if you can find one, or dead head a flowering shoot to make it form some side shoots that you can use.
I took some cuttings of the salvia (it's Trewithen Cerise) earlier in the year when I cut it back - they all took and grew on well and Wonky and Nut each have one and I've got some planted out in another bed - but yes, I'll take some more
along with some of the Salvia greggii Icing Sugar 
And plan to move Daniel late Sept/early Oct
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.