Just keep giving it as much water as possible, but don't let it sit in water. Paeonies hate root disturbance at any time, but digging it up now isn't a great time to move one because its in growth, although I realise you didn't have a choice. In digging it up, you will have destroyed its water take up roots, so the only thing you can do is keep it well watered. It will help to remove most of the topgrowth too.

Thank you so much. I'll keep you posted. :) X

....and when you plant the peony in it's final place dig plenty of organic matter in and please plant the peony very shallow. You may have to wait a year or two for it to flower again but it will. Peonies are lovely plants and will give many years of flowering.

Can I also add to make sure you keep it at the same level as was in the ground otherwise you will affect it's flowering in future years.

Try adding mycorrhizal root powder to the potting hole - it's not cheap but you might find a garden centre still selling the little sample packs for £2-3 (a small price for a treasure)