Are your purple peas Blauschocker? I grew them one year and they just went up and up - or rather they went up, then down when they got to the top of the mesh I had put up, then up again then back down, all concertina'd together. Very heavy cropper but I thought the peas were a bit tough - mind you they had had a tough life
I think growing my peas in the tunnel was a mistake this year, but the weather was so bad outside.... Each year when I see all the lovely pics in the catalogues I can't help but buy lots of different ones
I always come back to the sugar snaps though - no wasted pods and always crisp and tasty. I grew them the first year Thomson & Morgan had them in their catalogue bleep bleep years ago and have grown them ever since. Shame about the yellow MTs - it was a good pic in the Real Seeds catalogue