renort
You seem to be missing what is going on with the livery changes.
The main change is what has been referred as billboard titles, meaning bigger titles plus the big Spotty M and co.uk.
The yellow tail with the other small changes will be rolled out when each a/c is due a repaint, the new titles are not painted on the other a/c, decals are used.
It will take years, for the yellow tail to be fleet wide, you can take United Airlines for example. They have finally painted the last main line a/c which still had the 1993 blue with the top grey colour scheme.