Without knowing the details of history of operation and maintenance of the car, it is impossible to make accurate recommendation. Assuming this newer car had been taken care of, with scheduled maintenance done on time, and records kept, then Larry’s suggestion is correct. Motorway operation is generally a lot easier on oil than stop-and-go urban traffic, and I would even use up those arbitrary %5 left over afterwards.
On the other hand, if the car was poorly maintained, subject to frequent hard acceleration, lots of idling and other abusive driving practises, or if the history of newly purchased “pre-loved” car is unknown or doubtful, I would change oil before going on the long trip, because it would be the last thing I would want to worry about.
By the way, I would not solely trust the computer indicator, because it can malfunction, maintenance tech could forget to reset it etc. There’s no substitute to following (and keeping track of) proper maintenance schedule and regular assessment of oil level and its condition.