Went to the Caravan Show at Catterick Caravans today and on the way back called in at Ropers which is only about a quarter of a mile away.
They had a full selection of Orions on display all nicely presented.
On one of the new models ( can't remember the number now ) they had a concertina divider between front and back and on another there is a curtain doing the same job.
Bear in mind this is just a length of curtain material 1000mm x 1950mm with a tie back attached to a curtain track.
SWMBO quite liked it so looked on the Bailey Parts site for a price,wait for it,£95 including delivery and it does not even mention if the track is included.
Orion Dividing Curtain
I think I will go for Justin's mod if we go down that route.
From the same site you can buy 2m of curtaining 48" wide for about £35 and that is bad enough.