GTV dependant extension from outside of the UK

Dear Community,

I need to extend my girlfriend's dependent visa for GTV. I have a couple of questions, maybe someone has come across a similar situation:
1. Can she apply from outside of the UK? (On the gov website, it says it is possible during the initial application, but it is not clear whether she can apply for the extension from outside of the UK)
2. If her visa expires at the end of March 2025, what is the deadline for application?
3. Do we still need to provide proof of the relationship if we did so during the initial application?

Thank you in advance.