Rhubarb - it's dying!

I have three rhubarb crowns on my allotment. It was growing well and we had lots of lovely rhubarb, which we were picking and eating,  until two weeks ago. Now the leaves are covered with yellow spots and the stems are undersized and droopy (dead). The same thing has happened to two of my neighbouring allotment holders' rhubarb. We had a bad night frost here two weeks ago when a few holders lost their potatoes. Could this frost have affected the rhubarb at this stage of its development or is this problem due to a fungus? Funnily enough, the same thing has happened to my neighbour's rhubarb and we live more than half a mile from the allotment site. Any advice as to what to do would be appreciated ie. dig it up!

every year I am very proud of my rhubarb.  Grows like triffids.  This year, poor growth and looks small and sickly.

Same, plot crowns in sandy silt & manure now looking sad after a good start, home ones in clay (against a warm wall) growing well.

We didn't have all the rain the rest of you had.  It got wet, but no more than usual.

Yep it is the same on our plot's some are growing well but most have not grown at all this year. I only pulled three stalks of mine this year it is so bad. some people say it is the lack of frost we have had this year.