Hi Chris
It would have been better if you'd added this in the thread it refers to - just type in the box under the last comment & click on "Add comment". It just keeps everything together all neat & tidy, and anyone who's commented on your original question gets a notification that there's something new to read so they find it easily.

Leycesteria is often a present from the birds. It will grow to quite a large bush - worth bearing in mind when deciding whether to leave seedlings where they are, move them, or get rid entirely.

Very likely.

Next time you can say thank you by adding a comment to the bottom of your own question. That's the way it seems to work on this site.