Why it matters more than it sounds
Vehicle details typed by hand create near-duplicates: the same car under two records, history split across both.
Starting from the plate keeps one vehicle, one history, and one place to look when a customer rings about work you did last year.
What a lookup gives you
Core vehicle details, plus MOT and tax status and due dates where they are available. It is a starting point, not a substitute for checking the vehicle.
Keeping records clean
Agree who fixes a wrong record when it is spotted. Records degrade quietly when everyone assumes someone else will tidy them.