As far as I know we right bankers have always used the word and we did discuss this back in April:
http://wordsmith.org/board/showthreaded.pl?Cat=&Board=words&Number=145412

But meanwhile, from The On-Line Etymology Dictionary:

couch (v.)
c.1330, from O.Fr. colchier, from L. collocare "to lay," from com- "together" + locare "to place." Meaning "to put into words" is from 1529. Heraldic couchant is 1496, from Fr. prp.

couch (n.)
1340, from O.Fr. couche "a bed, lair," from coucher "to lie down," from L. collocare (see couch (v.)). Traditionally, a couch has the head end only raised, and only half a back; a sofa has both ends raised and a full back; a settee is like a sofa but may be without arms; an ottoman has neither back nor arms, nor has a divan, the distinctive feature of which is that it goes against a wall. Couch potato first recorded 1979. The first element in Couch-grass (1578) is a corruption of O.E. cwice (see quick).