Happened last week, and it's been very busy up at Warton understandably. A different scheme to the RAF ones, with a varied grey and small Saudi flag on the fin. Interestingly they're carrying ASRAAM. Maybe there'll be an announcement on that soon?
Lots of photo's are online:
UK AirShow Review | Saudi Friday @ Warton 24th Oct
EGNO 20th Oct 08
UK AirShow Review | Saudi Typhoon's second flight at warton
UK AirShow Review | 3rd flight of saudi typhoon @ warton