Unfortunately, as far as I am aware, there is no central place where serious case reviews are collated (although one can only assume the DCSF must have a copy of them all stashed away somewhere). In fact, unless things have changed recently, it is my understanding that the full reports don't even need to be made public in full - councils can choose to only publish the executive summary instead, so it is pot luck whether individual councils can be persuaded to send out copies of individual reports.
Having said all that, a team of researchers led by Marian Brandon, senior lecturer at the University of East Anglia, has recently published an analysis of serious case reviews between 2003 and 2005 so you could always try looking at that or contacting her for more information.
This is the third overview analysis and the DCSF tends to commission a new one at least every two years, so this could be a useful source if you are simply looking for information on recurring themes and lessons rather than for detailed information on specific cases.