Thanx Jim
So now I understand with all replies, that for mount to distinguish where exactly on earth longitude it stands, the onboard interface controller has been programmed with each timezone around the earth, which then with the current time can zero in and pinpoint the longitude and/or UT 'Universal Time'
Makes sense now !
I thought that was all sorted when/why it always asked the time in 24hrs, , but no, thats irrelevant to longitudinal specification and/or Times zones, hence UT
Learnt something
Rgrds all