What's wrong with this broad bean?

[Squash64]

A plot holder showed me this broad bean today.  There are raised
marks on the outside, and the beans inside have been eaten by something.
He said there was a grub inside but I think he'd squashed it - I couldn't see
it anyway.  (Sorry the photo is a bit blurred.)

Anyone know what it is, and if the marks on the outside are anything
to do with the grubs?

[Squash64]

[Robert_Brenchley]

I don't know, but all sorts of things go wrong with the odd pod or the odd bean. There are usually plenty of good ones!

[Unwashed]

Chocolate Spot I'd guess, caused by a Botrytis fungus.

[Squash64]

Chocolate Spot I'd guess, caused by a Botrytis fungus.

I googled chocolate spot and it does look like that, thanks Unwashed.

It would seem that the grubs inside the pods were not connected with the
spots though.