Can you identify this plant?

I suspect this is a common plant/weed but I just can't find it described anywhere.  It comes up in profusion each year, and I always dig them up - but am I digging up a prize cottage garden specimen?    The leaves are long, like streptocarpus, thick and with spiny protrusions on either side of the central vein.  Any help most grateful!

I'll drink to that.     We normally bring in a couple of dried teazle plants to get the pleasure of the Goldfinches feeding off the seeds in our garden over winter.  Seedlings are a small price to pay.   Cheers,   Tony.

Excellent - many thanks!  I'll keep them in - we love goldfinches!