Are the leaves of this plant still ok to consume?
The leaves can be naturally curly. Often they are curly because they have been damaged. It depends on how you are going to consume them. I can see some holes and even a bug, so there is some infestation.
I would look at each leaf individually, and discard any with eggs or webs. I like putting it in my normal English Breakfast Tea. I ended up talking off new shoots before they are attacked by the bugs and putting them in a glass of water inside. Then I can pick the leaves for a few days.
Otherwise see if you can get some "bug and insect netting" like this to cover it (after you have removed/destroyed the bugs).
I am happy spraying it with normal fly spray, covering it and waiting a few weeks before consuming it.