said...
The first plant that I asked about has just shown the first signs of a
flower:

http://www.cokey.co.uk/dump/flower1.jpg

http://www.cokey.co.uk/dump/flower2.jpg

As you can see it's a deep pink flower - any ideas as to what this is?

This is one of the few plants I know about: it's a willowherb. Could be
one of a number of varieties; the main thing you need to know is that if
it gets into your garden you will have one heck of a job getting rid of
it again. It's very pretty, but it's also very stubborn and about as
sterile as a bramble.
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