new pond help

There is actually a native water lily, nymphaea alba.

there are a great many water plants banned in the eu and uk, because they can spread rapidly in water systems and because they arent possible to control with stuff like glyphosate and manual digging.

 

Keep up @Philippa - it's hard not being 27 any more isn't it?

I get Water hawthorn and hyacinth mixed up too - always have to stop and think when hyacinth gets mentioned. I was thinking exactly the same as you until it clicked!

I grow Cotton grass [can't remember the proper name] in my pond @adamadamant , and it's fine in shade, so that's worth considering, especially as it's a vertical, and therefore useful for emerging damselflies etc. It self seeds, and I grow it round the pond edges too, but it does need reliably wet soil to thrive if you do that.
I moved this clump [it's in a container] nearer the house end of the pond, so that the water lily had more room to spread. It's in a much shallower site than the water lilies, and is mainly used as a marginal, but you can have it placed to quite a good depth IME.

 

Never watch Gardeners' World so obviously didn't see that episode.
I think the very strong black plastic cattle troughs with a built-in ballcock are much, much better than galvanized ones. The water seems to stay clearer in them and they're very robust.
I have two of them (buried in the ground). They're 2 metres in diameter and I've never cleaned them out in 15 years. They're full of newts.

 

@fairygirl at least Hyacinth and Hawthorn both start with H
I like that Cotton grass. I need something tall in my new little pond. I'd usually use the Cyperus but lost that last year. Good for the Damsels as you say.