VFR/IFR or Unknown aircraft
OK Chaps a little lesson on CAA regs!
It does not matter what flight rules the unknown (or infringing aircraft) is flying under. What matters is what are the flight rules of the traffic that the controller is working.
If the aircraft is IFR and in CAS it must be receiving a Control service. If the aircraft is recieving a RADAR control service the controller is required to take 5nm or 5,000ft against any unknown traffic that there is evidence to show is in the Controlled airspace concerned. (MATS PT1)
There is no discretion from the CAA, although they accept that an infringement may occur at the worst possible time and that the required separation may not be achieved.
Therefore if you have an IFR aircraft in CAS class "A" through to "D" the controller must avoid the unknown traffic.
P.S as for the clips of infringers it is highly unlikely that they will be realeased to a public forum where anyone (not just inerested pilots) may be able to access them.