In article , Mel
writes

I've found a website that sells a woodland seeds mixture including ragged
robin, pignut, ramsons, foxgloves, primroses, bluebells, bellflower,
selfheal, meadowsweet and various wild grasses (I could post the URL but I
don't want to be accused of spamming!)

Would these seeds be okay, or are they "weeds" that don't belong anywhere
near a cultivated allotment?

Ragged robin, pignut won't be a problem. Ramsons will spread in time,
but won't get established if you're digging annually. Foxgloves will
give lots of seedlings, but they're easily dealt with. Selfheal can
creep a bit, but shouldn't be hard to control. I wouldn't have thought
the primroses, bellflower and meadowsweet would be a problem. Depends
what they have in the grasses as to whether they're a problem, but if
it's a woodland mixture not a meadow mixture, they'll be wood sedges and
not a problem in a regularly dug allotment.

You haven't got anything in there which spreads by roots and underground
runners, which is what many of the thugs (ground elder, bindweed) do.
The worst offender for self seeding will be the foxglove.
--
Kay
"Do not insult the crocodile until you have crossed the river"