Thank you for the advice. I'm not sure how long she stated she was staying. Why? Will this impact her ability to get a fiance visa?

Hello there - hopefully someone can help! My American GF and I (British citizen) are planning to get married in the UK. We're going to apply for a fiance Visa. She's currently in the UK but coming to the end of a six month stay (3 weeks left). Can she start the fiance Visa application in the UK and ...