Bleeding the Clutch - R50 and R53
The location and design of the clutch slave cylinder can make bleeding the clutch on R50 and R53 MINI Coopers more difficult than it ought to be.
This video shows how to make a tool to keep the slave cylinder compressed which will leave less space for air bubbles in the slave cylinder.
Other things you could try are unbolting the slave cylinder and bleeding it with the bleed nipple higher than the rest of the body to allow air to escape or using a reverse bleeder to fill the fluid from the bleed nipple.