How to fill out FLR (M) with intention to get married!

My Fiancee and I have lived together in the UK for over two years. I therefore have the right to apply for an FLR (M). In the application there is a section that asks under what circumstances I am applying, only two options apply to me: Unmarried partner, and Fiancee.

I have been in the UK on a Tier 4 student visa which expires soon so I want to apply for an FLR (M) because we intend on marrying. Should I apply for the FLR (M) as a Fiance of british national or as an unmarried partner?

I understand that if I apply as a fiance, I only have the right to stay in the UK for 6 months, but If I apply as an unmarried partner I might be able to stay for 2yrs 6 months. If I apply as an unmarried partner, can I then get married in the UK to my British National Fiancee or do I have to apply as a fiancee and then apply again as a spouse after the wedding?

Thank you in advance.

You apply as unmarried partner, providing 2 years evidence of cohabitation and 'relationship akin to marriage'.

CR001 wrote:You apply as unmarried partner, providing 2 years evidence of cohabitation and 'relationship akin to marriage'.

And I can then get married with this visa?

Yes, although as a foreign national you can only register your intent to marry with a Home Office designated Registry Office.

If you marry you won't have to submit another FLR(M) application, you can remain on the FLR(M) Unmarried Partner visa you've been issued.