There was an article in Televison magazine May 1996 about the Nikkai Baby 10 colour TV regulator and how to build an equivalent using only a few components.
Download a scan of the article here:
http://www.digifixltd.co.uk/pdf/NikkaiBaby10Switch.pdf
Since that article is now nearly 20 years old, I don't know if all the parts are still available to build it, but if they are, it should be easy. The Baby 10 regulator gives an output of 10.9v which should be OK for your Pye TT1.