I think I might have a theory on this, I believe it all comes down to substandard battery holder contacts, while in the holder and connected across a one ohm resistor the voltage directly across the resistor drops down to 0.8 volts, leading me to believe the battery is under charged and doesnt hold as much energy as it did before, however holding the resistor directly across the battery terminals shows a terminal voltage reading of 1.2V, obviously the batteries werent discharged before I reconnected it back to the charger having them to peak under 15 minutes.
This makes sense I think I have to look for good quality battery contacts and see how that goes.