Strawberries and virus disease

Since my last post I made it back to the allotment and dug up the old row of strawberry plants. These all went straight onto the compost heap, except for 4 plants that have shown signs of growth distortion this summer, and bore no ripe fruit (the fruit failed to swell). I feel sure they have suffered from a viral infection, but goodness alone knows which one. I have found a list of 21 such infections online, on a site which offers lots of other good information about strawberry cultivation. 

To be on the safe side I put the affected plants complete with their root balls into an old plastic compost sack which I have sealed and I will dispose of them at the local recycling and rubbish disposal centre next time I go there. 

If anyone recognizes this infection please let me know.

It was too hot to do any more work up there. Next visit I must tidy up the other strawberry rows and plant up a new row with runners to replace the removed plants.