I don't think they would do terribly well as houseplants, Elaine - generally speaking, the light levels in a house will often be too low, and temperatures too high. Even hot country plants like lemon and olive trees don't do well inside, certainly not on a year-round basis. If you have an unheated conservatory, you might be lucky and pleasantly surprised, though.

According to my Houseplant Book, yes you can. They need a cool room, preferably one with a window which is open a lot of the time (they don't mind draughts at all, do rather better with a bit of moving, cool air), in a brightly lit spot that gets some sun if possible in winter. Place outside during the summer months, bring back in as cooler days arrive at the end of the season. Water moderately from spring through to autumn, but sparingly during winter, while its inside.

Thank you for that it is really helpful!

Unless you live in a very exposed area I would leave outside but move to a sheltered spot. If you must take inside then go for the unheated conservatory option. Remember if you leave the plant inside for too long then you can expose it to redspider mite and scale insect infestation.

Although we live in Italy, we are a long way up a mountain, and get some absolutely dreadful weather throughout winter - probably much colder than you get in the UK: we have two olive trees planted outside, and although it's best to protect them with fleece for a couple of seasons until they are established, they can stand far worse conditions than you might suppose, as long as they are planted directly into the ground rather than kept in pots. I had supposed you wanted them as decorative plants within your home rather than garden features, though.