Hi Plantmark,
I don’t see any supports in place for your Peas?
The second thing is they really shouldn’t need fleece at this time of year as they will take all but the hardest of frosts.
Onions don’t need fleece ever (except Spring Onions). Yellowing leaves usually indicate a nutrient deficiency but in this case I would suggest too high temoerature.
I personally haven’t seen this situation (Onions under fleece) before so I can’t be absolutely certain of my diagnosis. Wait to see what Charles suggests.
Don.