The sub-fuselage installation does indeed look more like a radiator, we need to find a source of far more detail so we can say definitively what it is - rad or oil cooler I presume the similar installation on the R-36 is for the same thing...there seems to be slightly more data around on THAT...I had assumed the radiators to be housed in the air scoop below the fuselage. Can you tell me if the Renard company was trying to use evapouration type rads? Since the wing root fillets are the radiators then I can see no through airflow and unless we have evap. type radiators - which RR tried and abandoned - I can't see how they would work. That would certainly place the weight of the 1,440 lbs weight (both Merlin 11 and 111 came in at that) relatively further forward and contribute to stability. This would give a similar position to the Spitfire.
Although looking round again - some of the R-38 pics seem to show the front of that inboard wing "fillet" filled in...so I'm slowly changing my mind back again. However - only that fairing brings the leading edge fully forward - the majority of it is indeed still further rearwards than the Spitfire's.
Incidently - it's worth noting that crash investigators put the loss of the earlier R.36 down to one of TWO causes...neither of which had anything to do with its air manners or handling But it's fair to say the extra power of the Merlin II "made" the design, over the earlier Hispano and Gnome et Rhone-engined attempts