Too any posters telling OP that she's not that big....everybody is different. Breast tissue can vary density - heavy in some women, and in others, well, not quite fluffy weight but for whatever reason, a lot lighter.
Also, too many posters saying get a better bra.
I could have had one crafted out of fairy dust, it wouldn't have made any difference. I was tormented at the constant pain. If you have large breasts and no pain, well that's great for you. But please don't try to minimise the debilitating pain of others.
Op, for the record, the NHS refused me, so am amazed they are offering this. However, I went private 10 years ago, and never looked back, 800 g removed from each.
Do your homework though. As I say, everyone is different, surgeon needs to go over this in fine detail for your requirements. It's not really a one-size fits- all situation.