Hi to all,
After reading all about the the 3 litre changes of oil I wondered if anybody had tried sucking out the oil with an electric oil pump ???

Clive If it ain't ***ked don't fix it

Anything is possible however, the remaining 4 litres will be in the valve gear and the cooler. Unlikely to be easily pulled out by a pump.

Bob 10MY (Sept 09) TD4 HSE Auto in Stornoway Grey (Now Gone)

08 FL2 TD4 SE Manual in Rimini Red (Now Gone)

Valve block is very small. In fact the oil cooler holds more than the valve block.
The most of the part of the rest of the oil is in the torque converter, almost the same 3 liters as the sump.
And, as you said, slim chances to pull it from there...
You can "wait" for the torque converter oil at the cooler connection lines, if you disconnect them.
As DIY method, use Valhalla method described here on the forum: http://www.freel2.com/forum/post137177.html#137177