Switching from Fiance/Fiancée visa to spouse visa

(Edited to correct a few words) Hello everyone,

I´m in Uk (England) under a Fiancée Visa. Soon my Fiance and I will register our civil partnership. I already begin to fulfill my application form to switch my fiancée visa to spouse visa and it asks for evidences of cohabitation covering the last 2 years, what is impossible if I´m in England with a Fiancée Visa. Well, should I consider that the form is made universal for any kind of situation evolving Spouse Visa and that the Home Office will be reasonable about my impossibility to submit evidences for such a long time? The whole process makes you so insecure about commit mistakes and not be granted that I would like to know about somebody else opinion or experience. I researched a lot, but nobody on internet mentions this particular detail. Those solicitors sites, even when talking about switching from Fiancée to Spouse, do not consider it is a very specific situation.

Another question I have is concerned about the proof of residence. To my Fiancée visa was "mandatory" a landlord´s letter (we live in a rented apartment). Is it also mandatory for Spouse Visa? We are able to have one and we also noticed our landlord that I´m living here, but I cannot find anything so clear as when I was preparing my documents to the Fiancée Visa.

Thanks everybody for the help. If anybody has questions about Fiance/Fiancée visa, please ask. I had my time researching for that and had a successful experience I can share. I know how hard it is to be confident on what you are submitting.