The August 1993 edition of
Modern Railways included a photo-feature on pages 478 and 479 of the expanding areas of service of the Networker Turbos, as they were then called. One caption states
The summer timetable also saw turbos extended from Banbury to Birmingham Snow Hill and a daily through Turbo-operated Paddington-Stratford on Avon (via Oxford) service introduced.
About this time MR also published a photograph of, IIRC, a Class 165 at Darlington while on a promotional tour. I can't lay my hands on the copy at the moment but I think it was sometime in 1992.
Added in edit: I've just noticed there is a photo of the first Class 166 on test at Cossington on the Midland main line in the March 1993 edition of MR.