Kevock Garden is offering a 3 litre pot size for £35.00 - they list it as 'yellow division' which should mean its the right plant. You can always ring or email them to ask how sure they are it will flower next year, but at that size, it's more likely to. Link to plant below, you'll need to navigate to the home page and then the contact us

https://www.kevockgarden.co.uk/plantlist/p1510_paeonia_mlokosewitschii_yellow_division.htm

Thank you Bamboo, I appreciate your help. I shall call them tomorrow to verify. I Did spot this via search but was hoping for a personal recommendation as some nurseries list them as ready to flower in next couple of years!, Worth the wait regardless!

There were other places offering tubers or roots, and one offering a 1 litre pot, but unlikely they'd flower in the next year or two.

I agree Bamboo, you've identified my bet, the sooner I plant the sooner they'll bloom!!

Once again, thank you

Kevock produce well grown plants and shrubs so I think this is your best bet!

Yes best bet! Thank you both for your help and advice.
Much appreciated