Greenock, you have no idea the amount of English who seem to call it
'Grenock' as in Greenwich.
Or if they get that right, then the emphasis on 'nock' gets them (see Gourock below).
It is simply
Green - ick
Gourock is another they almost always get wrong - Yes you are, by and large saying it right, but just don't put all the emphasis on the 'rock' at the end.
It is
Gour-ick, not Gourock.
Oh and Bearsden..... It is said as it is written, i.e. Bears-den, a den belonging to a bear, a Bear's den.
It is NOT said as one word as it were like
'Bearsden' or worse 'Beersden' or 'Beersdon'