Scanning the Chorley's Bomber Command Losses Vol. 8 HCU shows no Operational losses listed for 1660 HCU which was based at RAF Swinderby, Lincolnshire and operated pretty near everyheavy bomber varieties including the Stirling III, Hally V's and Lanc I's & III's during this period.  It was not entirely uncommon for aircraft of the Heavy Conversion Units or the Operational Training Units to be assembled for and involved in Diversionary Flights that sometimes flew in relatively large formations out over the North Sea and dropped window as a distraction for the Main Force Squadrons conducting Bombing Ops.   In and of itself that was valuable training.  These were sometimes referred to as "Sweepstakes Division" and some of the OTU/HCU assemblies could be upwards of 70, 100 or more aircraft.  When windowing and picked up on radar the goal was to distract and mislead the controllers of the German fighter defenses causing them to misallocate resources into the wrong sectors thus drawing attention off the Main Force Operations.
These flights generally turned tail and headed back to relative safety though that wasn't always the case and their were losses for the normal perils of flying as well as interceptions.

I'm not certain how one can find out as to whether any specific HCU was involved without accessing the individual HCU's ORBs if they even exist anymore.

Primarily though the role of the HCU was just that ... to convert aircrew onto the more complex Heavy Bomber aircraft that flew with the Bomber Command Squadrons.  After November of '44 the HCUs were placed under the umbrella of No. 7 Group rather than the control of the various Bomber Groups.

Someone may be able to access more specific details pertaining to the time period you have referenced but it was sometimes the case that HCU aircrew were actively involved in support of the Operational Squadrons.

Brian,
            No problem with sending the scans, but you need to email me so as i know where to send them.
Cheers.......Alan.