Hertfordshire has changed a bit since this article was created so a quick couple of corrections :
Hatfield - No longer has any aerospace industry at all, this closed down over a decade ago and has been replaced by a larger better equipped University of Hertfordshire which consolidated its entire set of campus's (Several existed in Hertford, Watford and Borehamwood) into a single new campus on the aerospace site. Has to be noted St Albans retained the law school.
Letchworth has a full name : Letchworth Garden City
You left off one of Hertfordshire's biggest towns Stevenage
Stevenage is home to the UK's Satellite/Space industry.