I'm pleased I left it.

About seven years ago we found a plant, seen in the extra, here. 
The summer "after Alice" I got some seed; and with typical skill and efficiency, managed to lose them.  Some days/weeks ago I spotted a weed I didn't recognise by name, neither did Jerra, so I thought I'd leave it and see.
Best guess after a trawl about:-
"Campanula trachelium, the nettle-leaved bellflower, is a species of bellflower. It is a Eurasian blue wildflower native to Denmark and England and now naturalised in southeast Ireland."

It's kinda looking like it's one of the seeds I lost.  We shall SEE(d).
I'll let you know.
;¬)