@Kea Try this:
Go outside where you have clear sky view. Not under trees etc.
Start GPSInfo.
Within a few seconds there should be a bunch of satellites, and at least 6 green ones in a few seconds, but it continue to have 0 used and no lock.
Stay outside, running gpsinfo, with the display on.
It took ~11minutes for me to get lock the first time.
If you keep running for another 10-15mins, the number of used sats will increase from the initial 6 to 10+
Subsequently it seems to be ~1-3 mins to lock.
I think it has old stale data if it hasn’t had a lock for a long time.
When running Puremaps, it often does not get a lock when the phone display goes off. I was running PM , cycling under clear sky, and it didn’t get a lock in 1hr after I started PM (but display was off), but then got lock in 2min when I kept PM onscreen.