We had a forum member here a few years ago who was in Argyll and grew them very successfully in a polytunnel, so they may well be worth you giving them a try.
I used to check them as soon as I saw cobs forming at around the 10cm size. If you carefully open the leaves on the first couple while still attached to the plant, you’ll soon get the measure of them. Then it is a matter of being vigilant with them as they produce several cobs per plant if you keep picking them off.
Here in the south east of England I used to be harvesting in early August and that was outdoor growing. The real sweetcorn would be 4-6 weeks later. They take very little room and don’t need pollination, so can be planted in a row or a block in whatever space you have.