New VTR From 25th February-Can someone please help clariify Large Letter RM?

I am hoping someone on here can please help me as I am getting more and more confused and stressed regarding the new VTR policy from 25th February.

I currently post 'Letters' and 'Large letters' by Royal Mail. I only post to the UK.

-Letter I use Amazon Buy Shipping and so they are fine.

-Large Letters I am currently using BPL through my OBA C&D which the inputs the Id numbers automatically onto my Amazon orders and uses 'Std UK Dom_1' or Std UK Dom_2' . My VTR is always 0% but this has been fine for the last few years since VTR changes last time.(scanned ones even show up on the VTR report).

Am I right in thinking that I won't be able to use the BPL anymore and that I will now have to do either:

A) Buy my large letter postage through Amazon Buy Shipping like I do for my letters,

B) Change my Royal mail account so I use CRL24/48 (instead of BPL) and then link my RM account to Amazon's Buy Shipping,

C) Change my Royal Mail account to Tracked24/48,

Any help on this would be very much appreciated as I really do not have a clue what I need to do and I am getting so stressed about it.

'Untracked Royal Mail 1st and 2nd Class letter stamps and franking are exempt from VTR if purchased through Amazon Buy Shipping (at no extra cost).' -Does this include 1st & 2nd Class LARGE LETTERS or just Letters?