As a treat my uncle would take me up to the top of the big huge crane (which I believe has been preserved) and we would walk along to the end of the jib and look down on the docks and all the ships below. He also showed me the original tunnel under the river. I have a feeling my uncle and my dad and me walked through this tunnel, which had a lift at each end to lift horse drawn carts up and down.
If you search Google Images for 'Finnieston Crane', 'North Rotunda' and 'South Rotunda' you will find lots of photos, past and present. There may be some here on this site too and on Virtual Mitchell.
The South Rotunda is currently lying empty and for sale, it hasn't been used since the Glasgow Garden Festival in 1988. The North Rotunda currently houses a restaurant.
No idea what sort of state the tunnel might be in now. It was STV's April Fools joke this year that it would be re-opening as a tourist attraction !!
As for Britain From Above, some great old pics of Glasgow there and hopefully lots more still to be added.