The CTV4's for Yellow Feather were contracted out to Ferranti (Moston.Wythenshaw) who sub-contracted the airframe construction to Bristol Aircraft, who sub-contracted the actual construction out to EMI. 60 CTV4 rounds for Yellow Feather were ordered at least with round serial numbers of 4001 to 4060. The TRE internal code for the project was AN.686.
It is likely that the order for the 60 rounds was made in 1953/54 and that 40 had been delivered to Malvern by June 1954. The first round fired, 4001 failed due to an air supply fault and a Bristol document from late June 1954 records that the actuator bellows used on the vehicle's control fins had deteriorated while in storage and modifications to the vehicles and replacement bellows were required for 45 rounds. The results for the firings of rounds 4001 to 4005 are recorded in a TRE report. The guidance receiver airborne trials involved the seeker being fitted to a Meteor NF 11 while a 100 Watt CW transmitter was fitted to a ground based "Lamp set" for target illumination.
I suspect that the primary purpose of this project was to investigate a CW front end for Red Shoes as the aerial design is almost identical to that of Thunderbird Mark 1. Ferranti had its own CW research project going as part of Red Duster from 1951 onwards and their CW receiver CTV4 rounds were flown in 1953/54. When a formal proposal for a CW Bloodhound was put forward in February 1958. it was originally intended as a upgrade to an advanced pulse SARH Mk 1 system proposed in February 1957 to give it low level capability and greater resistance to ECM on top of the extended range over the basic Mk 1 system. (The 1957 proposal was an upgrade for the last batch of 150 production missiles, which would push the maximum range of the missile out to that of the Type 83 radar by use of improved BT3 ramjets and more powerful Gosling 2 or 3 Boost Motors. An Accelerometer Assisted Range Gate (AARG) which would allow the missile guidance receiver to hold lock during the boost phase, a simple trajectory control system that got the missile to high altitude early in its flight and compensated for the effects of gravity and bigger wings and tailplanes).
The AARG modification did go into production Bloodhound Mk 1 as a modification. Most of the rest were done on the production Bloodhound Mk 2, along with the longer airframe originally proposed for the Command Guided Version that hit MoS's desk in April 1957 as an answer to the powered bomb threat. In a response to the Bristol-Ferranti 1958 proposal, W.H. Penley at RRE stated that one of the issues RRE had with the Bristol proposal was their knowledge of the effects of the missile's Twist and Steer control system was very much unknown as regards a CW homing guidance system, where on the other hand the RRE had extensive data on the homing dynamics of a CW guidance system on a Cruciform steered missile which I suspect came out of Yellow Feather.