The Reformation did not come peacefully to Great Britain. Land, money, and valuable assets were at stake. Monasteries and convents suddenly were under attack, instead of protection, by the crown.
Clergy converted. Or scattered. Or died.
Their buildings were left behind. Some in better condition than others. The best built remained standing in their communities. After the roofs were removed, some of them collapsed. Others were viewed as convenient stone quarries for other building projects. (Need some dressed stone for a bridge? Build a road or barge it from the old monastery.)
A few remain in ruined splendor to this day. This example near the border of Wales and England has become a tourist attraction.