Cohabitation And The Effects

Can I take my partner's name even if we're not married?

Yes, you can. It will probably make things simpler for you if you get that and trying to what's known as indeed a change of name because that will be something that your bank can or any other institution will want.

If we are not married, is my partner recognised as my next of kin?

There's no legal definition of next of kin. If you're going into the hospital, what you should do is to nominate the person you want to be your "next of kin", as it were. Tell the hospital staff.

Can my partner consent to medical treatment on my behalf?

Your care habitue can only give permission or consent for medical treatment if they are nominated. You need to get it arranged in writing with NHS staff.