I sowed mine last autumn and they put on a lot of growth over the mild winter but have never really got going so far, just a few random flowers and even though they were pinched out there is very little side shoot growth.

mine are not doing so brilliantly well either. I suspect it is down to the weather. it usually is one way or another.

Probably the weather,as the others say, but could be a viral infection, if they're stunted and speckled with white (not sure if you mean the flowers or the plants though) info here

https://www.rhs.org.uk/advice/profile?PID=248

Mine were sown in the autumn too, and haven't been much good. Only 3 small bunches so far and not much promise of more. Very disappointing.

Ours are growing very well, I'm pleased to say. Bought as tiny plants from a local garden centre this spring.

I was given some seed by a pal who collected off the ground while abroad. I put them in pots in my cold greenhouse and they germinated fine, then trasferred them to the small boarder at one side of the greenhouse, we had no clue as to what they were going to be. I soon found out , they took over the greenhouse!! they were perenial sweet pea, gorgious flowers and abundance of them too, unfortunately no scent.
Sadly it will have to go after its flowered, it's too vigorous.

Well Chino, if you manage to get the roots out so that it never grows again, you're a better man than me, gunga din (so to speak, I'm not a man at all!)... in my experience, once you've planted one, it'll be there forever...

Oh my god !! Have I made the biggest mistake, I grow toms in the boarder there but the pea plant was so big I was able to grow only one. I've cut most of the pea down now except two stalks which are still blooming then I will attempt to get it out without disturbing the Tom plant. Fingers crossed.

Seems to have a very long quite thin root or three that go down to Australia, rather than masses of small roots spreading out