I've twigged what is going on with the Lost Signal issue, and it is a bit lame, I'm afraid.
The Lost Signal setting is the "maximum time in seconds of sequential samples which repeat the same speed and power values, or heart rate or cadence signal goes to 0 value".
If you look at the results where the Lost Signal forces validation, the value is often in the thousands of seconds.
I realised that it looked the around same as the Actual time in seconds recorded for the attempt, and must be due to no heart rate monitor.
I checked and all the ones that failed on a long "Lost Signal" match exactly their actual time taken in seconds and also always have a 0 heart rate.
So the numpties are giving anyone without a heart rate monitor a Lost Signal count equal to the exact length of the ride, then forcing a validation acceptance.
Anyone with a functioning heart rate monitor should very rarely get the same signal for more than 10 seconds, so will generally be OK (one of mine was as high as 16 seconds for some reason).
The only option at the moment is to set the expected Average Heart Rate to 0 and the Lost Signal to something like 9,999 (2 hours 46 minutes).
I think I might contact bkool and suggest that they allow for people to ride without a heart rate monitor.
Geoff