Q.lemon tree
The tree is about 2 years old and stands about 1 metre high. It seems to have spread out normally, but has long fronds emerging from it, almost a metre high. Is this normal?

It is possible that you have had suckers grow out from the root stock of the tree.
Suckers should be removed as soon as they appear at the base of the tree.
Here are some links to help you.
https://www.gardeningknowhow.com/edible/fruits/lemons/how-to-grow-a-lemon-tree.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/can-grafted-trees-revert-to-their-root-stock.htm