''King Lear,'' starring Sir Laurence Olivier in the title role, airs on syndicated stations in many cities on Thursday, Jan. 26, 8-11 p.m. (check local listings for specific stations, and for repeats). This British Granada TV production was reviewed in London by Christopher Andreae in the May 2, 1983, issue of the Monitor. Mr. Andreae found Olivier's Lear ''an instant classic . . . toweringly self-assured, a commanding, detailed study of a man old before he is wise. . . . The grand old man of British theater casts over the entire proceedings a brittle, crackling magic.''