Here is another article in a British newspaper: http://www.expressandstar.com/2008/06/30/handcuff-shortage-feared-as-firm-goes/ . They take the same angle, focusing on potential shortages. Both articles also mention the protests against Hiatts several years ago regarding Hiatt handcuffs used at Guantanamo Bay. Again, Hiatt handcuffs were removed from service at Guantanamo early in the creation of the prison there. But why let facts get in the way of a good protest?
Here is something from the Birmiingham History Forum: http://forum.birminghamhistory.co.uk/showthread.php?t=15301&highlight=handcuffs . Some posters speculate that they were run out of the country by protestors. I believe it was a simple business decision. There were only 15 employees at the factory. The business will be easy to move and will be better integrated with the rest of the US based BAE businesses that were formerly part of the Armor Holdings Products Group.
For a history of the Hiatt company, see this link on handcuffs.org: http://www.handcuffs.org/hiatt/index.html .