I remember this well. In the circumstances of our resources at the time, and the fact it was pre-Hillsborough, it was a pretty well conceived development, although inevitably under Swales, conspicuously not executed, the ‘private boxes’ being a case in point. Think their location would have been terrible in terms of the view. Also not sure where you would get the food etc… in there. Only conceivable way is a lift at one end of the Main Stand or the other, as getting access via a gantry at the rear along the roof from back to front seems logistically challenging, especially given how close the furthest back seats in the Main Stand were to the new roof.
I seem to remember some boast about the Main Stand roof, at the time it was built, being able to withstand a huge amount of snow being deposited on it, which has to be one of the bizarrest football development boasts ever!