Can anyone assist on watch this watch is please

[stewoz]

Trying to locate the model of this watch and what approx. value it may be for insurance if it is of any value
the watch is boxed in the orginal box  but the strap is damaged in is 1950/60 erra I think
the red watch  box contains information stating it is a Calender watch? with instructions that match the watch
the guarantee just has the serial no
but I am unable to locate any information

Information of the back of the watch 530000 pics attached

removing the recover there is a number on the reverse on the gold back plate of 685419
Many thanks in advance Ste

[Iktomi]

This is a 50s/60s era Zodiac dress watch. The dress watches did not pertain to any particular model but you may be able to locate the specific watch in the catalogs.