Sorry, meant New Shoots post about john innes compost.
To be fair, I could pass for a blueberry bush after some of my gardening sessions, when I roll back inside covered in grot and with leaves in my hair.
I would go with new plants if you can, just because the old ones will be so pot bound and hungry, they will take a while to recover.
If you want to save the old ones, this is drastic, but works most of the time and can revitalise a pot bound plant. It can also finish them, so be warned.
Knock them out of their pots and tease roots out, so you can get as much of the old compost out as possible - you will see what I mean about it going dusty. An old kitchen fork can be useful for this. Trim the roots back by about 1/3, do the same to the top and replant, working new compost in around the roots as you do. Make sure you water regularly and look after them a bit after this treatment. Get this done fairly soon, before they start to get going for the new season.