I'm struggling to find dark teal bridesmaid dresses on a high street budget....

I'd recommend taking a look at quiz clothing?

https://www.quizclothing.co.uk/clothes/00100012320.html

This is the closest to that one I can find.

Debenhams often have dresses like this on sale in the quiz and little mistress sections x

Susie Booth is correct about Debenhams. I have just bought a petrol blue one (like the above) for my daughter/bridesmaid from Little Mistress. It is stunning and she will be able to wear it afterwards.

Have a look on eBay, my friend got her bridesmaids dresses off there for around £30each. They came from China though, so be mindful that their sizing is smaller than UK sizes. She ordered a size bigger than needed as there's plenty of material if it needs taking out, but also the option of taking in. Xxxx

TFNC Boohoo and Asos do some lovely bridesmaid dresses xx