I've read else where that it is possible to just buy the cruise control stalk from a dealer and fit it as my van (scudo 120 multijet 2.0l 2007) already has all the other stuff fitted as original to make the system work. My dealer says it will need new ecu ..... Any help appreciated.

YES.....I used Conrad Anderson (0121 247 0619), back in 2000, when I got my motorcaravan that is built on a Scudo 1.9TD base. It's worked excellently all the time.
I would recommend..hope that they are still there?