It was a first for me too Garp, and using the amount of chicken meat that came from 2 frames is probably a bit of overkill in a 1 kg onion batch of gravy that finished at about 3 litres of concentrate or double that diluted 50 /50. It is strong enough to even dilute it out further if necessary.
I was just going off what had apparently been customary practice in early BIR days and probably didn't think the quantity through very well. If the BIR's back then had 2 or 3 frames boiling away in their base, there would have been a considerable meat transfer, although probably not the amount I used. I'll probably think it through and make an adjustment next time. However, the base actually came out really tasty and makes good curry so it didn't do any harm. It smelled absolutely great when it was cooking and it is pretty tasty on it's own. I would not call it a neutral base by any stretch.