A twenty-sixth episode, "The O'Rourke Affair", was scheduled for production in August 1968 but was unmade due to an ITV strike.
On 17th March 1967 the series theme tune was released as a single: 7N 17279 on the Pye Records label, where it was performed by Roy Budd with the Tony Hatch Orchestra. On the label the show's title was given as "Mr. Rose Investigates".
In the first series the retired Chief Inspector has a countryside retreat at Rose Cottage. In the second he has moved to town, and the hi-tech Flat 5 of Floribunda Court. A floribunda is a modern group of garden roses.
From the second season, Mr Rose is driven around in his mini, registration ETE 328F.
John Halifax gets his name from Dinah Maria Mulock Craik's 1856 novel "John Halifax, Gentleman", whilst Robert Trent's is said to allude to E.C. Bentley's 1913 work "Trent's Last Case".