Beverly and welcome to the forum. Instead of tacking your request onto the end of an old thread, you would get better response by creating a new one. On an old one like this, many folks might not even open it to find your new entry.
Anyway, I expect it may be hard to find a new slave. I had no luck 10 years or so back looking for one. You might try the sources listed in this thread as well as Small Ford Spares in England, www.smallfordspares.co.uk as they do have a lot of parts.
A better option than a new cylinder, in my opinion, is send your old one to Whitepost Restorations, www.whitepost.com, to be bored, sleeved with brass and rebuilt. They offer a lifetime guarantee for probably less than the cost of a new one that might last 5 or 6 years. I have had many cylinders done by them over the years and they do beautiful work. I have never had reason to use their warranty.
Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)