Overtime is available in the UK, but I wouldn't touch it with a bargepole
We are only allowed to decline OT if we have what A$A decide is a valid reason. They tried to get what amounted to a court order requiring us to contact work within one hour of them leaving a message, and to remain within two hours travel of work, 24/365, unless we had prior permission. They failed, but it gives you an idea of what they are like to work for.