Don't worry, you still have plenty of time provided there are no frosts. Here in France the maize farmers are still watering their crops and waiting for the corn to ripen. Next year you should either get your sweetcorn sown much earlier or grow an 'early' variety.
In any case, the cobs will ripen far better on the plants than by being cut. Once cut, they will tend to turn to starch rather than maximising the sugars.

Sueno - where are you in the UK? We are already getting frosts at night here in Moray.

Oddly enough Bilbo I have had quite a good crop this year!

Had problems with germination of one variety which I got replaced, but a second variety I grew germinated quite well!

My plants were a lot shorter than normal but I don't know if this is down to variety or the season,possibly a bit of both!

I harvested my crop last week and the cobs were quite large. The top inch on some of them hadn't matured but the other six to seven inches were lovely!

Hi

I've only done sweetcorn a few years now but mine always seem to ripen later than anyone elses. I've had a good year with them this year, the odd one got eaten by mice I think lol but I've only just picked them, I wouldn't worry about leaving them a bit longer on the plants.

Mine have been eaten by earwigs and woodlice!