Help identify these plants please

[Flymetothetoon]

They have sprung up from some new top soil and have allowed them to grow because not a clue if they are nice flowers or something unwanted that will just take over

Looks like a weed called Lambs quarters. Get rid of it before those tiny flowers set seeds.

That's a Chenopodium. They have small insignificant green flowers, but are one of the better "can be eaten like spinach" wild plants. I hadn't hear the name "lamb's quarters" but it's the same thing. See for example www.wildfooduk.com/edible-wild-plants/fat-hen/

Oh thank you both. They will be removed this minute!

Make a salad with them @Flymetothetoon.