Complex sentence: Like most Nottinghamshire mines Cotgrave continued working through the NUM declared 1984-85 miners' strike however the view by many was that this allegiance to the then Conservative government was betrayed.
Split into simpler sentences: Like most Nottinghamshire mines, Cotgrave had continued working through the National Union of Mineworkers-declared 1984--85 miners' strike. Many took the view that this allegiance to the then Conservative government was betrayed.