on iberia.com
lfc84
you should be able to do the transfer online on iberia.com however the Combine my Avios function is well-hidden
Login to your Iberia Plus Account
Click "Iberia Plus" in the top header
Click "my Avios" and then "Avios Balance" in the left-hand nav
Scroll to the very bottom of the page and you will see "combine my avios" in very very small letters
You should be able to do the transfer online instantly there
You can do the 2nd transfer online to BAEC at avios.com
Good luck ^^