Geoff - it's not often you're wrong but you are right again ! Went back to G.C. armed with 2 of the afore mentioned baskets and explained the problem and was immediately asked what trays I bought - polystyrene or plastic . Told him it was polystyrene and he took me over to the bench and showed me the rest of the pansies that had been affected which was all of them , not just the Morpheus , all of which were in polystyrene. Turns out they had been purchased from a grower called Ambroses and they had to be binned. Showed me all the ones they had grown themselves and they were in plastic trays and were all fine and dandy. He said he would be speaking to his brother tomorrow about it and said Ambroses were the dogs' XXXXXXXX and they have never had any issues with them before , which I agree with as I've bought pansies from them for years.
I got a full tray of new pansies and an apology. 
They were in the plastic trays.