Contract – Mental capacity to contract – Defendant’s mental disorder – Knowledge of the other contracting party – Averment of knowledge – Onus of proof – Whether the separation agreement is voidable by virtue of the defendant’s mental disorder – The bases on which matrimonial property is to be divided between the claimant and the defendant – Mental Health Act, section 2, The Property (Rights of Spouses) Act, sections 2, 4, 10, 13, 14 and 15