Unfortunately within KashFlow you are unable to add in an Accounting Period prior to the one already entered :

I'm trialling Kashflow as the upgrade of my last software failed to transfer all the data of the previous 3 quarters before I'd done the final quarter and year end tasks for last year - 2019 - 2020. So I've switched services and I'm having to re - enter everything from scratch. I've discovered that Kashflow won't allow me to do this. Can you make this possible please ?