Window channel

You're just missing the ferrules for the side curtains?  DrClock had some custom made years ago - wonder if he has some still available?  Electric wire ferrules or plumbing chrome sink/toilet pipe (remove yellow gasket).

I don' t have any extras left.

You can go to an electrical supply store they have metal crimping sleeves that will work. 

I have 8 of the CMC ferrules I am willing to send out.  I didn't use them because they are a bit crude.  I used the ones Alan had made.  They are very nice.

Just about any large, DIY store plumbing department (B&Q, Homebase, etc) has water feed pipes in the plumbing section under "kitchen" or "bath" that are chromed and flared just like what you are looking for.   The newer versions have an integrated nylon seal, but the older versions are flared and carried for repairing older faucets and toilets.  They will be much longet than you need, like 12" to 18" long, but they are easily cut to the length you'll need.

IIRC:  I believe that you need something that will accept a 5/16" mount pin, but measure what you have, or bring it with you to the DIY store to make sure it is a good fit.

Thanks everyone for your help.   I have a plumbing parts warehouse near where I live so I will go and explore what they have when they are open again on Monday.   C