Tractor Driver - after reading the AAIB report, it seems clear that the real problem is the approved beacons (Tech Test 500-12Y) because they are having their signals suppressed by the WWPLBs (wristwatch beacons).
The WWPLBs perform a double function in that they give a Man Overboard (MOB) alert to the rigs in case anyone falls off as well as providing homing to an individual who may have got separated from the other pax during an aircraft ditching/crash. To that end I would not get rid of them.
I would rather replace the crew and liferaft ELT/PLBs with ones that aren't suppressed so you can always find them. Whilst I understand the theory that having fewer beacons transmitting should help the rescuers, in the case of G-REDU it hindered them instead.
It should have been a straightforward job to home to the beacons on the liferafts, especially as these should have been the strongest signal - but the suppression technology made it far more difficult.
In short, I see no reason to review the WWPLBs and every reason to review the aircraft equipment.