Posted: 23/03/2016 at 10:40
The first one looks like Arum maculatum aka Lords & Ladies, Cuckoo Pint, http://wildflowerfinder.org.uk/Flowers/L/LordsAndLadies/LordsAndLadies.htm
a wild plant - it depends upon your garden style as to whether it's a weed or not - its fine in woodland gardens etc, but not really for a formal border. However it's a pain to get rid of but dies down in the summer. If you remove the seedheads to prevent self seeding it'll help a bit to stop it spreading.
The second one looks like a Lychnis to me, possibly L. coronaria - think they're called Silene nowadays rather than Lychnis. A pretty plant which self seeds itself around http://www.bbc.co.uk/gardening/plants/plant_finder/plant_pages/7569.shtml
Not sure about the last - it looks a bit like one of the willowherbs which can be a nuisance - but it could be several other things too - see what others think - someone else will be along soon