Issue with proof of address timeline

[Ranger18]

Hi. I'm new here.
My wife was granted her spouse visa in March 2016, her current Visa expires in December 2018.
We were living together in London until September 2016, we then moved to live with my parents in Yorkshire where we have stayed till December 2017.
We have letters of cohabitation while we were in London until September 16. After that we were not responsible for bills while living with my parents also struggled to open a bank account for my wife as we didn't have a proof of address for my wife from the previous 3 months at our current address. Due to this we also had difficulties getting a GP. Eventually got one and have letters from July/August 17. Eventually we convince my parents to allow us to pay a utility bill which was required for us to apply for a joint tenancy at our own place.
Basically we were planning to stay with them for 4-5 months but ended up staying over a year. Now since December 17 we have plenty of letters in our names after moving into our own place.
My core question is for the period between October 2016 to July 2017 we have nothing in between in my wife's name.
Can I submit a letter from my parents confirming our residence with them along with our difficulty getting any correspondence in her name explained in a cover letter.
Any help is much appreciated. Thankyou in advance.

[Londoner007]

A cover letter will be required to explain this. And any proof to show you were in Yorkshire.

[Ranger18]

Thanks. Someone I spoke to mentioned a statutory decalaration from my parents signed in front of a solicitor. Would this and a cover letter explaining the situation be sufficient.

[Ranger18]

A cover letter will be required to explain this. And any proof to show you were in Yorkshire.

Thanks. Someone I spoke to mentioned a statutory decalaration from my parents signed in front of a solicitor. Would this and a cover letter explaining the situation be sufficient. Also we have travelled overseas to her brother's wedding, I know it isn't necessary but is it a good idea to send travel tickets confirmations and photos from trip.