I have the same year model WM 250V-F which has the power feed, bought at Harrogate exhibition' in 2012. I stripped the apron down back in 2018 to see if I could solve the oil leakage problem which gave me the chance to see what the inside of the apron looked like& clean it out.N.B.if you go down this route be careful you don't lose the small leadscrew drive key, anyway I cleaned the oil window as best as I could & replaced the oil with some SAE 32 oil ( hydraulic ) which I had a surplus of instead of dashing out to buy transmission oil.
The drain plug is underneath the apron, M16 hex socket plug, same for filler plug on the left side of the apron, I wrapped the drain plug with PTFE tape as the thread was a Chinese fit… somewhat slack, so far it helps, it still leaks but easily topped up every couple of months.
My conclusion is that these machines have some casting porosity with the apron, maybe on this particular years model ?. My intention is to change the filler & drain plugs to hex head M16 bolts modified to take a couple of Dowty washers, it won't stop leakage due to casting porosity but will seal the drain plug better, in the meantime I can cope with cleaning up some oil drips.
George.