Eriobotrya japonica, Loquat.

do not keep it in a plastic bag for long.. especially if the bag is in sun ... pull the bag down.. and wrap it with an old towel or something .. and keep the towel damp ...

ken

Yes, thanks ken. It's sitting in it's pot now.

Looking at the picture again you seem to be in the U.K. This tree is not hardy in colder areas (below -10c in winter) and you're unlikely to get ripe fruit due to insufficient heat in summer. But it’s lovely small tree.