I was always told to remove the male flowers from a cucumber plant or the fruits will be bitter, I then read "female flowers need to be pollinated with the male flowers or the fruits will not set", then I read "only outside growing of cucumbers need to be pollinated by the male flower". I grow mainly in the greenhouse and the vine grows well to 4ft and cucumbers form all the way up, but then only the top fruit starts to swell and the rest shrivel and die. I also read "remove all side shoots as like with tomato growing leaving just the cucumber". So, is there an outdoor and indoor Seed, as I buy seed every year and nothing on the packet denotes Garden or Glass house. I also tend to buy female only F1 variety, but on the whole if I get three cucumbers over the season I am lucky, but I see on youtube or television they get over a dozen fruits. Where am I going wrong?
I think what you're looking for is a parthenocarpic variety. A parthenocarpic plant is one that does not need any pollination to set fruit and is perfect for greenhouse cultivation. I'm guessing that you've been planting either gynoecious (has only female flowers but requires a variety with male flowers for pollination) or standard varieties. There is a nice discussion of both types in the answer to this question.
This site has a list of parthenocarpic varieties, with information about each variety's growth habits, disease resistance, fruit, etc., that you may find useful. One note on that site: it was apparently translated from another language, so there are some inaccuracies in the way the author refers to some thing. For example, the text talks about cucumber "bushes" and "shrubs" rather than "vines", ad it has an unusual way to spell "cornichon".
EDIT: There's no reason to put gravel at the bottom of a pot, as suggested in comments, because that does NOT improve drainage and, instead, makes the drainage worse! See here and here for scientific explanations as to why that is.