@ossobuco,
It's looking like I'm going to have to learn to love this pot with a very small chip in the lid & a larger bit out of the main pot.
OK, then.
Looking on the brighter side: the exposed cast iron parts are likely to rust a little, yes?
Which is rather closer to the colour of the enamel than cast iron, yes?
Anyway, this has been the most useful bit of cast iron ware I've bought. I get a lot more use out of it than the (big) casserole. Especially in summer.
So I will just have to adjust to imperfection then.
Thank you very much, all, for your suggestions & the research involved. Much appreciated.