Is there anything i can use on my plum tree to encourage it to grow?

Looks like a very small specimen, and I would guess the main problem is it hasn't rooted down into the soil properly yet. How well did you prepare the soil before planting? Is there a good depth of topsoil?
Once it gets going it should grow away quickly but you may a little wait. I would just give it a little liquid feed during the growing season to help it on its way if the soil is ok.
Where did you get it? Normally plum trees come as much larger specimens. If this was from a dealer or a shop then they weren't being very generous to you!

Thanks for the advice. I dug in some top soil to the whole area about 2 weeks before the tree arrived and then added a little more when I planted the tree. i have some organic liquid seaweed so i will start applying that to the tree and learn to be extremely patience.
If i've remembered correctly I ordered the victoria plum tree from thompson and morgan's website along with a chocolate vine, which also doesnt seem to want to grow.