I very much doubt I'd have the same difficulty now in the XF...
Definitely not - even the 'plain vanilla' XF which I have is much more agile than the W211, so your more sporty version would be pretty impressive over the Scottish West Highland roads.
I've got a lot more grey hair than you though, so I'd be happy to have even more 'waftability' over cornering performance.
I think this American advert sets out nicely the differences between the two Marques....
https://www.youtube.com/watch?v=Vi08c_siQys