"nightjar .uk.com" nightjar@insert_my_surname_here wrote in
message ...
Any idea where I can get a double cylinder?

I buy mine from a traditional locksmith, rather than one of the
places that
calls itself a Security Centre and charges extra for doing so. Most
DIY
sheds sell Europrofile cylinders, but I'm not sure whether they do
the
asymmetric type you need. However a symmetrical 45/45 would only
mean that
the cylinder protrudes and extra 5mm on the inside, which is less
of a
security issue than if it stuck out further on the outside. If the
cylinder
is marked to show that one end should be on either the outside or
the inside
of the door, it is probably biased, the way yours is, and will not
let you
operate it from one side if there is a key in the other. Mine are
reversible
and allow me to work the lock from either side, irrespective of
whether a
key is in the other side or not.

Colin Bignell

I emailed one of the companies I found online and the reply I got
was:

As the key pushes a clutch, inside the cylinder, from side to side,
there isn't a conventional cylinder available that allows you to
operate the lock from the outside, if the key is on the inside.

So I'm not sure a lock such as you describe even exists! So now I'm
not sure what to do.

Angela