TOMTOM Go Essential speed cameras

JJscoops Registered Users Posts: 3
New Seeker
I have purchased 2 x Go Essentials, both say it has a 6 month Speed Camera trial installed (which I can see in the menu). When I try and purchase the Speed camera subscription, I enter the serial numbers first 2 digits to be told it is not compatible? If it is already installed it must obviously be compatible, how can I extend the subscription when the time arrives?