Selfsufficientish.com

There really is no such thing as 'a raspberry virus'. They are a whole host of different viruses,and they are practically ALWAYS present in ageing raspberry beds,Why so common? They use aphids as vectors.To put the icing on the cake,they also use soil born nematodes,so in answer to the above query,yes you should re-site new beds.
Lastly,the viruses show usually in Autumn with marking/yellowing/deforming of the leaves,so don't be fooled by 'clean healthy new growth'.
If the leaves are clean and healthy as they fall off,that's what you're looking for.
Remember,these are cheap to buy,we're not talking Mulberries here,but I understand the attraction of a freebie.

Ok thanks, being the lazy sort I mighty try the cut right back option first and if that doesn't improve things next year I could remove them then!

What are the disadvantages to moving a raspberry plant now? It's got some fruit on it/

You don't get any fruit at all. It's a bummer of a job that takes time. You won't be able to plant much in the space this far into the season.