1/5 New Style - replaced Julian's in 1582 (9,8)
9 Insects of the order Dermaptera (7)
10 Bewitching (10)
11 Philosophers who regard human existence in a hostile universe as unexplainable, e.g Kierkegaard and Heidegger (15)
12 Any one of Spike Milligan, Peter Sellers, etc. (4)
13 German poet and novelist, author of "Faust" (6)
15 Beach material found at Brighton (7)
17 Former name of Harare, capital of Zimbabwe (9)
19 Generally not covered by an insurance policy (4,2,3)
20 John ---, Scottish engineer and the road surface named after him (7)
21 Design made of small pieces of coloured stone or glass (6)
23 Wyatt ---, participant in the O.K. Corral gunfight (4)
24 A retired person (3-3,9)
27 Deciduous shrub of the genus Plumeria (10)
28 English Whig statesman (7)
29 Like a Manx cat? (8)
30 Site of temples removed for the construction of Aswan Dam (3,6)

1 1925 novel by F.S. Fitzgerald (5,6)
2 Spanish river flowing to the Mediterranean (4)
3 Scott Joplin's kind of music (7)
4 Julius, Tanzanian president 1964-85 (7)
5 With 1 across, a form of plainsong (5)
6 Doubles? (4-6)
7 Carer in the administrative grades (7,7)
8 Girl's name (7)
11 La Manche to the French (7,7)
14 A district of Manhattan for globetrotters? (6)
15 Plaster rendering (6)
16 Founder of the Boy Scouts (5-6)
18 To expurgate a book, word from Edinburgh doctor who produced "Family Shakespeare" (10)
20 Infective disease transmitted through the bite of an infected Anopheles mosquito (7)
21 A port city in northeastern Sicily (7)
22 Christmas comic books (7)
25 Real surname of George Eliot (5)
26 A sepulchre (4)