I must live in a parallel world because here it’s significantly easier to get an Android phone fixed than an iPhone. Plus you don’t have to pay Apple extortionate price for parts.
Here Timpsons provide the service outlets for Samsung, although that probably does not help you. But it is basically the same price.
And that’s for battery. Just take a look at screen repair if you want to cry.
Samsung.com/uk says £79, so I don't agree with that.