Spacing veg for next year

A few images of things growing and how the spacing between them isn't quite right.  Looking forward to making adjustment next year.

Courgettes

These need a LOT of room, at least a metre apart. Mine are about a foot apart (nearly forgot to always use imperial units for the allotment).  Makes it tricky to get to the middle one and the leaves shade everything else.  Probably not enough food for them either.

Second, leeks.  Too close to the courgettes and I think they should be further apart.  Maybe need a bit of earthing up.

Finally, sweet corn.  Spacing s OK but I should have put a few more in I think.