I think this an original 7-Eleven Corsa Extra non team bike from the late 80's maybe the very early 90's.
The 0 X on the left hand side of the bottom bracket denotes size and model. So you have a 60cm (0) Corsa Extra (X).
Top tube cable guides were replaced by internal cabling at the start of the 90's on the Corsa Extra frames.
Nice frame good luck with the sale.