One thing about the internet is that it does provide you with a lot of good information, and some outright garbage. I still do a lot of the work on my vehicles as well as my Son's when I am up in Maryland.
On one issue with his Jaguar, the factory/dealer way to change the oil pan was to remove the transfer case, etc. Cost to change a $140 part was close to $2000 at the dealer. Online at a Jaguar forum I saw where a few people had posted about changing this same part. It seems that there is a tab on the cast aluminum oil pan that gets in the way of removing the part. By cutting off this tab, it drops right out, without touching the transfer case. When you look at the replacement part you see that the tab is not really needed and the vehicle will operate just fine without it. It did not impact a gasket surface or eliminate any of the mounting bolts. Just this one little hint from a private mechanic took a 20+ hour job down to a 2 hour job. It was also something easily done in my Son's garage and it did not need to go to the dealer.
To be fair, the dealer was going to insure that everything was done according to Jaguar and everything would be exactly as it left the factory. On the other side of the coin, the removal of the tab did not affect the operation of the vehicle, which we changed out 30,000+ miles ago, and the savings stayed in my Son's pocket.
My point is that when you run across a repair that seems next to impossible, do a thorough search online and you MAY find someone that knows how to do it much easier.