Giles. I have had a Jaguar XE for just over three months. It replaced an XF which I loved and I was concerned about it being a bit smaller and indeed being considerable slower than the 3 litre XF
I have found that in the back of the XE there is still a good amount of room and the people I have taken in the back, including my 78 yr old sister have got in and out with no issues and they say they have been comfortable in the back. Just need to be aware the roof does slope when getting in and easyish to catch one's head.
Performance now I've done 3,000 miles is extremely good for a 2 litre (180 diesel) and I have found economy to be excellent as well achieving over 50 mpg most of the time and on a recent long distance run just over 60mpg.
I am very happy with it.
Regards
David C