SET O and home office Reference No

[Riffatshahid]

I am on tier 1 general and will be applying for ILR soon. I did two extensions to complete my 5 year residence requirement. My second extension was at premium service centre. My approval letter does not have any reference number. However, letter of approval for the first postal extension (more then 3 year ago) has a reference number.
Now I wonder how should I answer ''home office reference no'' question on set o form? Should I leave this question blank as I was not issued any reference no at the time of my second extension in January this year? Or should I use 3 year old reference no? Will they be able to track my record if I use old reference no? What is a better option, shall I leave this column blank or mention old reference number?

[Kmaj007]

Better leave it blank, they will track your record anyway, but should avoid giving any info which is not pivotal to your application

[Riffatshahid]

Better leave it blank, they will track your record anyway, but should avoid giving any info which is not pivotal to your application

Thanks for reply. However, the question on Set o form is ''Your home office reference no if you have one''.
Does that mean I only need to provide the reference no on my most recent application? Will it be ok if I leave it blank as I don't have any reference no on my most recent application? What will be the repercussions if I provide reference number from my 3 year old application? Gurus, Moderators please advise.

[Riffatshahid]

Please Advise.