Posted: 13/07/2017 at 19:20
They do grow in pots which is why they are also sold as House Plants but they will only usually "do" happily for a certain length of time if housebound.
However, if by "established" you mean anything above a couple of foot in height, I'd be careful about digging up - particularly at this time of year. I doubt they would be happy in a gravel situation TBH.
They are frequently available for sale - perhaps you would be better off leaving the plants for the next owner and starting again.
Bear in mind too that if you intend to remove something fairly obvious from your garden that your buyers have seen, you need to specify that you are removing them before you exchange contracts.