Some friends bought this tree that was grown in a pot, five years or so ago.

http://tinypic.com/r/wluj6b/7

It's brought into the house from outside in the garden for a couple of weeks
every christmas. Although it was a bit pricey initially it saves buying one
and throwing it away every year.

Would anyone be able to name this type of tree please and especially
grateful if anyone knows where to buy a *pot-grown* one. (i.e. the roots
have not been chopped to put it in a pot).

Ideally it could be purchased not too far from the North London area in a
reasonably priced nursery. Thanks for any advice.