Clarification on "6 months or less" in family visa limitations

Hi all,

I am a British citizen, and my girlfriend is from Bangladesh. We have been together for just over 3 years and living together for just over 2 years.

She is currently about halfway through her graduate visa (about 11 months left), and we are planning to apply for a partner/spouse/family visa.

On the government website there is a section titled "When you cannot get a family visa" which includes the following:

You’ll usually need to leave the UK to apply for a family visa if either:

• you have permission to be in the UK as a visitor
• your visa is for 6 months or less

When it says your visa is for 6 months or less, is this referring to the amount of time you have left, or the full length of the original visa, i.e. this is excluding short-term visas?

The reason I ask is that we were planning to apply around March next year, but if it means 6 months or less remaining on the visa then we want to make sure we apply sooner so that we don't cut it too fine.

I assume from the wording that it is just saying that people on short-term visas cannot apply from within the UK, but just want to make sure. Thank you!

Secondary question: is there much benefit to being married before applying or would it not make too much difference given that the time we've been living together is over 2 years? My salary is over the threshold so we shouldn't have any issues with the financial requirements. We were considering doing a court marriage just to get that legally sorted and remove any doubt, but if there isn't much benefit then we won't consider doing this vital.