A. 1) If you set the location yourself (so not a designated tide point), you will need to input the high and low tide times into the G-shock move app. Once complete, the watch will then calculate the tide times for that location from then on.
2) Please check to see if you have set the watch to 'London' as the home city - if the watch is set to UTC or a different time zone it is likely that this will affect the tide time.