I might be wrong, but I think that I have read that the model is the AS Autograph and that, because few of them were made, they were each called after a town or City. I don't think the different place names signify different models though, just different individual saxes in the line.
I think that the Autograph series was made as a variation from the TJ RAW saxes but that Andy Shepherd collaborated with the maker going to and fro with suggested modifications until he was happy to put his name to it.
From the website....
"Andy puts his signature on the bell of this incredible saxophone as a seal of approval that the Andy Sheppard Autograph Series tenor is of the highest quality craftsmanship. All are hand built and finished in Lenham, Kent by Dave Farley of Worldwind Music. Only 100 of these tenor saxophones will be built and each will be individually numbered and engraved with a different favourite World city where Andy has performed.
Every finished saxophone will be play tested by Andy Sheppard to ensure each instrument meets his exacting performance standards. This final quality control process is accompanied by an audio recording of Andy testing the saxophone over at his Bristol studio along with a signed CD."
Andy Sheppard Autograph Series Saxophone