Sorry if you are confused.
Your original question was related to the difference between FLR & ILR
However, it seems that the visa YOU have is a little bit different because you have been living together as a married couple for more than 4 years.
YOUR visa allows you entry as FLR for 27 months, BUT you have a special endorsement attached to your visa (KOL required). This means that you only need to pass Life in UK Test, then immediately you may apply for ILR.
Belle, please read the UKBA link I included before.
Here it is again :-
http://www.ukvisas.gov.uk/en/ecg/set...guage#21490059
Where an applicant has satisfied all of the requirements for Indefinite Leave to Enter (ILE),
except the KOL requirement, they should be granted 27 months Leave to Enter (LTE).
During this time they can, at any point, satisfy the KOL requirement in the UK and apply
for Indefinite Leave to Remain (ILR).