JAGUAR XK8 Gearbox Oil - Star Question

Q
I have a 1999 XK8 with 60,000km on the clock, and I want to change the gearbox oil. I know that you have advised in JWM that the oil should be changed only by a dealer or a specialist, however I live 1,000 miles away from the nearest dealer and there are no specialists in automatic gearboxes here in Spain. Besides, when I once went to the dealer and asked for the oil to be changed, they looked at me as if I was from another planet and said that it was sealed for life, so they simply wouldn't do it.
I am a retired mechanical engineer and quite capable of carrying out the change. I do all the maintenance - in one day I've changed the primary and secondary tensioners, chains, chain guides, water pump and thermostat with parts sourced from the UK.
I believe that the oil should be Esso LT71 141, but I intend to use Audi/VW oil part no. G 052 162 A2, which is the same at a third of the price. The drain plug is on the upper left side of the gearbox, I have to siphon out the old oil and pump in the new one until the oil starts to leak from the plug, and I also believe that I must be very cautious regarding the oil temperature - I have the Auto Enginuity tool from Gendan but am unsure of the temperature range.
One last question, to remove the remaining 5.0-litres (approx) of oil from the torque converter and oil cooler, would it be practical to loosen one of the cooler pipes and run the engine, regularly topping up by the same amount that comes out until clean fresh oil starts to flow?

A
While we cannot comment on the use of a VW oil, the following should be of assistance.
1: There is a drain plug in the sump pan, retighten to 30Nm
2: The filler plug is at the right rear corner of the transmission (looking from behind), refill until it overflows the hole and refit the plug. Then start and run the engine from cold engaging each gear in turn and leaving it idling in Park. Remove the plug again and continue topping up until fluid just trickles out of the hole with the (transmission) temperature between 30 and 50°C. If the temperature exceeds 50°C stop and let the car cool completely before trying again.
3: We would not recommend draining any fluid while the engine is running as the risk of damage should a seal or bearing run dry is too great. A safer option would be two oil changes, 5,000km apart.