AS1 Land Registry query

I’m currently attempting to assent a property after a parent’s death. I’m both the executor and beneficiary.

I got my application returned for the 2nd time from the Land Registry - it’s correctly executed as a deed but now my dates don’t match! Because I dated it when my neighbour witnessed it. But the application, the AP1, is dated earlier.)

I don’t think I can now legitimately backdate it, although they’ve written in the application to sign any amendments! I might have to make a new application (they say they can’t advise what to put for the date). Would I be best cancelling this application to assent altogether, or would they be ok with my backdating my AS1 to match the date on the AP1?

(This is probably a ridiculous schoolboy error on my part. I thought I might have made a mistake, but I didn’t expect it to be the date!)

Many thanks for any advice!