Can you explain exactly what went wrong, is there a gaping hole in the side of the block or is it just the cylinder head gasket which has failed?

Very rare for a cylinder to blow unless due to a conrod failure, also rare these days.

As Galileo said, if you can provide any extra information about exactly what failed, it would help ... but unfortunately, the engine was 7 years old and had done nearly 90,000 miles. Catastrophic component failures are rare these days, but they can and do still happen.