The message
from Martin Brown contains these words:

In message , Joanne
writes
I understand that sweetcorn should be harvested when the juices are milky,
and when the stringy bits on top are brown and dry. However, my
corns' bits
are stringy and dry but the cobs are still very small.

So, do I wait until the cobs are larger, or do I harvest now?

It has been such a poor summer that it isn't too surprising they are
struggling a bit. I'd guess they are still not yet ripe even if the
strings are dry. Mine usually come ripe around the end of September.

Poor pollination might also be a factor if the cobs are short of grains.

You could always pull a couple and see how well they cook. Fresh produce
just off the plant always tastes sweeter...

My cobs are also well smaller than usual but I have been eating them for
the last two weeks and they are excellent - just small. In fact I now
have one or two which are what I assume to be over-ripe (though I now
realise from the rest of the thread that ripeness is more complicated
than I was thinking) in that the grains are caving in slightly - or is
that just lack of water?
I would definitely try a cob.

Janet G