I think you’ve confused the issue if you sent them a 1202. That’s the form to transfer to the UK, not from it!
Yes to be clear, I m leaving the UK CAA to the IAA. SFIM'S reply seem to be the other way around.
my reply is the correct way round, i have just done it successfully, the wording on the top of the 1202 is confusing unfortunately.
if you look at page 2 you specify there what you want to do (to IAA from CAA)