Can anyone identify this plant?

[Sheneval]

My neighbour has this rather nice foliage plant growing alongside her plot but although she thinks it may have been in a packet of seeds she sowed earlier this year, she has no idea what it is.

Any help would be gratefully received

[Peppermint]

It looks a little bit like Orach (German Mountain spinach) plant on the Real Seeds website

Vegetable Seeds : Salad Crops other than lettuce

I remembered seeing something purple and popped along to see.

[Scarlet]

My vote would also go for red/purple orach - I'm growing some this year and I don't like it! I won't grow it again

[Sheneval]

Peppermint and Scarlet - Thanks to you both - much appreciated