From tv.com:

   Echo Four Two was a 1961 British TV series spin-off from No Hiding Place in which Harry Baxter is promoted to Detective Inspector of the Q Car Squad of E Division. Thirteen episodes were planned, but the final three were cancelled due to an actor’s strike. A second season was discussed, but not commissioned, freeing Det. Insp. Baxter to return to No Hiding Place.

   I kind of doubt whether any viewable episodes exist, but here’s the theme song. Turn this one up. Way up!