Matthew Barry has published a practice note on the law of unjust enrichment on Practical Law. The note, titled Remedies: Restitution, provides an overview of the principle of unjust enrichment, the elements of an unjust enrichment claim, defences to unjust enrichment, and remedies for unjust enrichment, with illustrative examples from the case law.
Matthew has also contributed to a practice note titled Restitution: Change of Position on the change of position defence in the law of unjust enrichment, based on original material by Michael Watkins and KV Krishnaprasad.
The note on the law of unjust enrichment can be downloaded here, and the note on the change of position defence can be downloaded here.