What is wrong with my Kaffir lime tree?

[Indigopearl]

I was given a kaffir lime tree as a present a couple of weeks ago. It looked really healthy when it arrived but has since started to drop a lot of leaves. Some leaves all look infected (see pictures). It is in a sunny window and gets water with citrus feed when dry. Any ideas?

Picture on the left is leaf miner.

www.gardenersworld.com/how-to/solve-problems/leaf-miner-fly/

Not sure if the damaged leaf in the picture on the right is related.

Thanks for your help. It does look like leaf miner. I am not sure if this is what is causing all the leaves to fall of though or if that is something else.