Tbh most of them are a mess. Before the changes it was

306 would interwork with the 308 on Sunday only

43/44/45 would interwork during the day but then interwork with the 52/53 on evenings & Sundays

52/53/54 interworked (54 was standalone on Sundays)

57/57A interwork (still do)

X7/X8/X9 interwork (still do to some sorts)

55 standalone

46/46A/51/51A interworked

Now it's an absolute mess. Its hard to tell what interworks with what