Moving away from Flat rate VAT

Accounting
1

I am moving away from flat rate VAT. HMRC have told me that it will be effective from 31/12/16, when I was expecting it to be from 1/4/17.
What do I do about all my logged purchases since 31/12/6, which were showing as no VAT, as previously I could not claim VAT back. Do I need to go into each one and change it to show the VAT amount? Is there anything else I need to do (I have unticked the Flat Rate VAT box in my company details)

2

Will you be on cash or accrual basis for vat?
and
Were you cash or accrual basis for FRV?

3

I was, and remain on a cash accounting basis.

4

If you know your vat amount for inputs since 31/12/2016, you can do one journal to account for input vat amount this will save you editing individual invoices else editing each invoice is the way foreword

5

Thanks! That helps a lot.