that looks like insect damage. check for small caterpillars [sawfly larvae I think] underneath and rub them off with your fingers, wear gloves if you are squeamish. you can remove the worst affected leaves without harming the plant. other than that it looks to be in good condition.

I was worried it would turn out to be bug related, I'll have a look and see if I can find anything. I try not to kill things so I hate finding out I have yet another plant prone to infestation!

Thanks for the advice!

Hmm nothing on the leaves at all, maybe they all feasted and left already!

Hi, welcome to GoY, it could be that the other plant in the pot has meant that the bottom leaves have been kept damp, which has caused this, if it's just the lower leaves, I would remove the other plant from the pot, then you can please yourself whether youremove the affected leaves or not, the plant will get rid of them anyway over time, that's how the trunk is formed, Derek.

Thanks Derek. It is the lower leaves but the ones round the back are in full sun and not touched by the other plants at all as they are only in the front, so they are bone dry!

Hi, in that case then, it sounds as though the plant is just getting rid of some older leaves, nothing to be worried about, Derek.

Thanks Derek, I'll cross my fingers in that case then :)