For what it cost me it isn't worth the cost of sending it back and trying to prove it is reading in error. I have a couple of GPS Rx decode and RF front end modules which only cost 3 or 4 pounds during coving lockdown but didn't get used. I will have a contrast and compare session with these and also the Garmin GPS12xl which I think can be set to output the NMEA messages for reading on a tty terminal.
Testing is on the move might be the tricky bit.