Patio peach tree help

I assume it will stay in the pot long-term?

What size pot is it in now?  It will probably prefer a terracotta one rather than plastic, and not too narrow (helps to prevent it blowing over in the wind).

Use John Innes No3 compost rather than multipurpose, as it retains water and nutrients better.  I'd also add general purpose fertiliser such as FBB or Growmore.  Make sure you water it regularly.

It was in a little pot when I bought it but I will be putting it in a much bigger pot tomorrow I didn't really want to put it in a terracotta pot because I was planning on putting it in my greenhouse with my lemon tree over the winter and it would weigh a ton in a terracotta pot, I've got the John innes no 3 and will add some some grow more and also look into getting some fish fertilizer after all I am in cornwall there must be some down here  thanks for the info