If you have the space to plant them in the ground I would highly recommend you do that.
Apple trees will grow in pots but ....
You only have to forget to water them once and they will die.
In a smallish pot in summer they will need watering at least once a day, every day.
The Bramley even on a dwarfing rootstock is still a vigorous tree and would perform a lot better in the ground.
And, you will get bigger fruit and more of them when they are planted in the ground.
If you don't have the room for a conventional orchard why not edge your veg garden with them and train them as espaliers or step-overs, they take up very little space. See here for and example ...
http://lodgefarmplants.com/Step%20over%20Apple.htm
What ever you choose, good luck and I guarantee you will enjoy your greenhouse too
