10-10-10 and 8-8-8 fertiliser

You could just even repot it with some fresh compost. Looking at your image, there seems plenty of room in the pot to give it a good top dressing of fresh compost which will give the tree a boost of nutrients.

I can get hold of fertiliser that has an NPK of 20-20-20, evenly balanced like Growmore but far more potent, which means you have to be more accurate in application as you would only need a third of what you need if using standard Growmore.

 

It looks well enough to me without feeding this year.
Make sure it gets lots of sunshine to ripen that new wood.