It’s easier if you grow your own. I used to be a terrible nail-biter but I started growing them 7 years ago. Doesn’t work for everyone due to the nature of their jobs, but my job is all done on a computer.

I’ve had a few people mention my nails but I just tell them I like it like that. Much better than bitten fingernails for sure

I know you said High Street.
I will post this anyway.
I buy from eBay.
The thing here is that they come in bundles of like 500 at almost no kost.
And all the ones i have bought so far come in 6 sizes,
Since there are so many, i use the bigger ones, on the finger who need this, also tend to use “size 2” on 2 different fingers.