When you take your GPS abroad, there are a few things that you will need to do when abroad to tell the GPS that it's not in the UK:
1. Ensure you have a minimum of 4 satellites showing and when you do....
2. Calibrate the Compass
3. Change the Position Format to the relevant Grid (there is no pre set grid for France or Spain and so you should use the UTM/UPS format). A list of Position Formats can be found on the link below
4. Check that the Time is set to 'automatic' as this then picks up local time when locked on to the satellites
5. Check that within the 'Heading' setting that the 'North Reference' is set to 'Magnetic' as this will account for local magnetic variation.
In the UK, it wouldn't matter too much if you forgot this step, as the variation is so small. However it is a critical setting when abroad because of the much bigger magnetic variation
6. Have bought a paper map that says somewhere that it is 'GPS Compatible'. This will have the UTM/UPS system on it as well as Lat/Long. The UTM system is just easier to use