Many thanks for the replys and info. I did suspect that the info I was recently given, ie that the facility had been moved to Liverpool was suspect as I still recognise voices that have been around on 118.85 for years and not a "Scouser" among them !!.
Having just looked at the technical page on the aiport's website it confirms that SSR (Secondary Surveillance Radar) is provided to Teesside by link from Great Dun Fell Radar which is near Penrith. (That big white ball that can be seen from miles around).
The Airport's Primary Radar is a Plessy Watchman System which I can remember was chosen years ago as it fitted in with and matched the radars at Leeming. (Well that's what was reported on local media at the time).
Thanks again.