Or the reason those rates are "throw about" is because years of under investment in training and retaining staff means that there are too few to do the job, and those that are there are in some cases no longer willing to do overtime purely for good will and time in leu (which may never actually come as they're always short staffed so don't have the staff to give you that time back), but want the money to make up for losing time with family etc?
I'm going to guess that rate is either agency, or something along the lines of double time with an overtime multiplier, something that is or was the norm in most industries. IE you are asked to work overtime you get say 1.5x normal, if you're asked to work additional nights you get say 2x normal, etc and they are cumulative, something that used to be intended at least partly as an incentive for management to not run massively short staffed or take the mickey with requiring overtime (as the cost was such that management recognised it was cheaper/better to actually have the staff to avoid it happening too often).