Determining apple tree size?

So last year I saw an advert by Thompson & Morgan offering a free Golden Delicious apple tree with a code, you just pay the delivery. It sounded like a good idea at the time, I purchased a large pot like my other fruit trees and bought all the potting mix in anticipation of this tree arriving.

What I actually got in the mail was what I could only describe as a twig I call it my pet apple tree, because it's clearly not old enough to do anything productive but I still care for it in the hope it will grow up one day. I put it next to one of our Gala trees for comparison, a few quid more and I could have gotten a full size one

So I noticed my pet tree is budding. It's way too small to support fruit so I was about to pluck them off, but then I realised I didn't actually know how big this thing was going to grow. I mean for all I know it's one of these.

It still has its label, but if there is a means of determining its final size from these codes; it's beyond me. I don't suppose anyone here is able to get anything from this label that may shed some light on how big this tree will grow?

If patio fruit is not contained it should reach height and spread of 2.5m (ideal conditions and looking after) as it is on dwarf rootstock http://www.thompson-morgan.com/fruit/fruit-trees/apple-and-pear-trees/T10395