With regard to Cloud ceiling and the ICAO minimum of 1500ft for a departure within a control zone, this is brought about by the following two requirements (under standard ICAO rules);
1. No enroute flight below 500ft AGL; and
2. Requirement to be 1000ft vertically from cloud in controlled airspace.
Thus with a ceiling (more than 50% sky covered) of 1400ft, it is impssible to comply with both those requirements.
The answer to that situation is to get a Special VFR clearance which removes the requirement to be 1000ft below the cloud.
Regards,
DFC