What subtype visa for settlement to apply for civil partner?

Which type of visa (settlement) to apply for where a person already has a civil partnership in the UK, is it family reunion?

If it is, what title should I put in applying for a settlement visa as I'm so confused on what to apply for (subtype-settlement) and I can't afford to make a mistake this time?

My situation is, I'm already married in the UK via civil partnership and I'm so confused on what to select under settlement category. My partner is a British citizen and I'm applying for this visa in the Philippines.