Casio Waveceptor 2734 WVA-105H watch not working

You can use the manual to manually reset the time. After you succeed in setting UK time zone, wait until midgnigth: it should synchronize itself with the time signal from Germany. If unsuccessful to do so, it will keep attempting to synchronize itself at 1, 2, 3, 4, and 5.

Read the manual to figure out how to place the watch on a window sill. It might be better to be outside.
Keep in mind that the success of the operation depends on meteorological conditions.
Good Luck.