Hi JayCee
Interest really picked up AFTER lockdown which I guess is because so many people are online. I actually got a couple of decent offers and have taken a deposit pending final payment and pickup after lockdown. I sent videos and service receipts for the out of town buyers.
I got a 2009 X5 3.0 SD diesel because I needed 4wd but the 550i is a much nicer drive and the 4.8 V8 is a total honey. Also mechanically it’s been really good, for the E61 you just need to expect to replace the airbags and compressor at least once, and I did the cam cover gaskets which is a common thing. Otherwise it was just keeping up with fairly standard regular servicing.
The 550i is a great family and load hauler and fantastic tourer. If you’re just after a weekend car, that opens up a heap of options, you may not need something as big as the E61.
Good luck with your search!