34. For the purposes of Part 9 of SSCBA and Part 9 of SSCB(NI)A, the prescribed circumstances in which persons are treated as residing together are that spouses, two persons who are civil partners of each other, or two persons who are parents of a child are absent from one another—
(a)where such absence is not likely to be permanent; or
(b)by reason only of the fact that either of them is, or they both are, undergoing medical or other treatment as an in-patient in a hospital or similar institution whether such absence is temporary or not.