......and another thing.
The trip over there highlighted just how utterly piss poor Jaguar Sat Nav is.
The system in the mighty Signum is far superior.
I'm surprised you have so many issues with satnav. Unless you are expecting them to give you a hand job on the way.
Suspect the system in mine is slightly older than yours (Its something like gen2.1 hdd or similar). It does what it claims - it gets you to the specified destination.
My gripes with the Jag one, is you *HAVE* to use the touchscreen to enter stuff in, whereas the NCDC for example, could be completely controlled from the steering wheel. Fortunately mine has Jaguar Voice, and surprisingly works well, apart from postcodes, due to an extra step/guess needed.
But I never use postcodes anyway, due to their all round shiteness.
None of the roads on the route I expect you took have changed around these parts, unless you went along A43, then the jnc with M40 has been remodelled to arguably make it flow better (it doesn't), so its not like it would have you driving in a field etc.