RichardvdS

Hi All,
Thank you for the useful replies. 
Out of complete desperation i ended up replacing my geyser thermostat thinking that this was perhaps faulty and not turning off once it reached  its set temperature (hence the higher than expected electricity usage). This despite having tested the original thermostat to confirm it was working correctly.
After replacing the thermostat and setting it to approx 50deg i removed all timing settings and left the geyser on. The idea being that this would inform how much power (and time) it would take to raise temperature of 200l of water from approx 20 deg to 50 deg without any influence of timing settings. I then monitored the power usage via the CBI App and could clearly see the power draw of +-4kW over the next 2 hours (or so) at which point the power reduced to 0W.  Considering the CBI controller was still "on", the water had clearly reached 50 deg and the thermostat had correctly cut power to the element. The CBI App also reported a total power usage over this period of +-8kW (as would be expected).
After further interrogation of my CBI app I have FINALLY realised the following.....
Note:
my CBI App has two controllers linked to it i.e. 1 for the Geyser and 1 for the Pool. my DB was rewired on 09 June When my DB was rewired in order to split loads into essential and non essential, the electrician inadvertantly switched the wiring of the two CBI controllers. Consequently the readings on the CBI Geyser App (previously pool pump) appeared to indicate an increase from 5kWh to 20kWh for the geyser. It is now clear however that the +-5kWh (prior to 09 June) is reflective of the pool pump (i.e. 0.75kW x 6hrs) and the 20kWh (after 09 June) reflects the geyser usage (4kw x +-5hrs). As these results are reporting on the same Geyser App graph it appeared that the geyser usage has increased significantly when in fact it was due to a change in wiring resulting in the geyser usage being reported alongside the pool pump values.
Similarly the CBI Pool Pump App (previously Geyser App) has reported a similar trend with readings dropping from +-20kWh (prior to 09 June) to +-5kWh (after 09 June).
Finally SOLVED!!!!!
Thanks for everyones replies.
Richard