Answering my own post, I managed to get 4:2:2 working (of sorts) by streaming to the pc and viewing 4:2:2 content with vlc.
The Enigma2 webinterface is a bit of a pain but the best solution I found is a great little util called.....
DM7025-VLC AUTOPID LOADER version 1.0
When setup, it connects to the 7025, grabs the pid data etc then loads up vlc with the correct url pid info etc.
There is a 1.3 version too but I didn't have any luck with it.
Boswell