Courgette, unsure what is on the leaves!?

kelibremner

Can anyone tell what this is on my courgette plant!? it's on about four leaves, and is there anything I can do!?  

Lyn

They look a bit starved, they need a big space to themselves, they’re very big plants, once its planted out in the garden it should be ok, give it about 3’ space of its own, in the meantime you can just cut off the offending leaves. 

kelibremner

You're a gem Lyn, thanks.