In reply to all:
Thanks.
I think I need a new watch, it is getting a bit old now.
Yes, it is getting a gps signal.
I don't really understand how these things work but if it knows distance then it must know where I have been?
John, is yours a watch that uses GPS data for elevation, not barometric data?
I have a mate who's is working fine but I know it is a much better watch and may not be relying on the GPS data to calculate ascent.