You can grow seedless cucumbers in England in a greenhouse. Other cucumbers require pollination. Can you give us some indication as to what happens to them so we can answer your question? Having them in big pots could mean they get over-watered. How big are the pots? What type of growing medium do you use? Do they set flowers, but no cucumbers?
I grow cucumbers in the greenhouse every year successfully. I do keep the doors open day time, so that bees and other pollinators can come and go. I plant them right into a raised bed and fertilize every 3 weeks with a dose of fish fertilizer and 0-10-10, to keep the bloom going and keep them growing well. I have wire trellises that they loop over and around, and we keep them picked. We make refrigerator dills in the late summer, and while it says they are good for only about 3 months, we are still eating the ones from last August and they are crisp and delicious
Yes, agree with Farmerdill, cucumbers in a pot would subject the roots to temperature extremes, moisture issues, etc. If you can plant them in soil or a bigger tube like a half barrel they might do better
I know people grow cucumbers in Self Water Containers with great success. I'm growing them in containers but they are large containers. What kind of soil are you using? Cucumbers seem to need more water them many other plants.
Cornell University has some great information on growing vegetables. In looking at the entry for cucumbers, I think the two things that seem most important to me are:
-- fertile soil
--and (I think maybe most important) cucumbers are sensitive to cold. You want 70F during the day and 60F at night for optimum growth.