SOLUTION 683:

ACROSS 6 Hoover, 7 Venice, 10 Galileo, 11 Loupe, 12 Dior, 13 Magma, 16 Dumas, 17 Lear, 20 Heart, 21 Karachi, 22 Renoir, 23 Zagreb.

DOWN 1 The Godfather, 2 Doulton, 3 Bells, 4 Bellamy, 5 Titus, 8 Eleanor, Rigby, 9 Rosa Parks, 14 Curtain, 15 Mercury, 18 Maine, 19 Pro-am.