You probably know this, listed companies including vast multinationals almost always file within weeks or a handful of months after the year-end. For several reasons including shareholders needs to know, transparency. I assume external auditors are there throughout the year to made the post year-end phase easier.
But it shows what can be done.
The Albion run a slick organisation, TB/PB would've known the final result and balance sheet from accurate management accounts last summer. No subjective valuing was required for example.
