Yes, it does apply to restricted patients.
The combined effect of ss72(1) & 73(1) is that the Tribunal must discharge a restricted patient if it is not satisfied that all three of the following are true:
(i) that he is then suffering from mental disorder or from mental disorder of a nature or degree which makes it appropriate for him to be liable to be detained in a hospital for medical treatment; [72(1)(b)(i)]
(ii) that it is necessary for the health of safety of the patient or for the protection of other persons that he should receive such treatment; [s72(1)(b)(ii)];
(iii) that appropriate medical treatment is available for him; [s72(1)(b)(iia)]
BUT for restricted patients the Tribunal then also has to decide whether the discharge is to be absolute or conditional. If the Tribunal is “satisfied that it is not appropriate for the patient to remain liable to be recalled to hospital for further treatment” (s73(1)(b)), the discharge must be absolute (ie the patient is discharged from detention once and for all).
If the Tribunal isn’t satisfied about that, the discharge will be conditional (s73(2)), In which case the patient is discharged from detention and can leave hospital subject to conditions, but remains “liable to be detained” (s73(3) which means, in effect, that they can be recalled to hospital in future if necessary (s73(4)).