He could unilaterally revoke his consent to the assignment; this would revert responsibility for the breaches back to Alvita, as the previous leaseholder

He would be able to pursue Violet for the breach, on the basis of her continuing contractual liability, give that she was the original contracting party to the agreement

Within any s.146 notice sent to Carter, Tobias could request that Carter remedies the breaches AND compensates Tobias for his loss if he is to resist any attempt to forfeit the lease

He would NOT be able to seek compensation from Carter as this is only a contractual remedy and Carter is not an original contracting party