Where can I get a sofa to fit up my narrow stairs?

[MrsFogi]

We have stairs that it seems impossible to get sofas up (hence my old tiny sofas are stuck downstairs). Does anyone know where I can get a sofa (or better still sofabed) that is self assembly (so that I can get it up the stairs in bits rather than the back getting stuck!)?

Message withdrawn

A lot of sofas these days seem to have detachable arm sections -I only know this as we, too, have an upside down house so getting new sofas up a staircase that goes round on itself was an issue.

I think its just a case of going around all the sofa places, getting catalogues from mail order sofa companies etc and asking which come in sections or have removable arms and then choosing (as opposed to choosing and then finding you can't have it )