As much as I enjoy flying with cadets, I'd rather they stop flights for a month and fix any problems that may have resulted in these recent events and then continue, rather than just carry on with chances of it happening again.
Sadly, stopping flying would achieve nothing, other than 100% safety. Whilst the January incident was unfortunate, I suspect this one will reinforce the argument that in today's busy airspace,
all users should use a transponder with a height readout capability. Having flown at weekends around the home counties, and had to avoid numerous gliders and light aircraft, who we either spot with Mk1 eyeball, or with direction from ATC ("Contact 11 o'clock, no height information" etc etc), this thing is waiting to happen.