Coffee Break Cryptic

30 September

Across

1 French friends turned back, receiving good letter from Greece (5)
4 Substitute endlessly on his feet? (5-2)
8 Speech-making in lab extension? (7)
9 Cracking up in southeast river (5)
10 Online message taking precious time (5)
11 Nuts cracked in shade (5)
13 A girl has to live somehow (6)
15 Odd result? It's brilliant! (6)
18 French leader with clever story (5)
20 The best stuff is packed with energy (5)
23 Remove blockage from net (5)
24 French number in cargo (7)
25 Friend follows child without reservation (7)
26 Silly Billy from New York receiving accommodation (5)

Down

1 It proves playing is playful (8)
2 Woman's mealtime prayer (5)
3 Missionary position in central Wales (7)
4 Cutter is dreadfully chesty (6)
5 Some boats easily seen sailing (2,3)
6 Top side improperly put down (7)
7 Annoy an informer (4)
12 George Michael's first attempt to include English as school subject (8)
14 Eccentric not on strike (7)
16 Family member with article that's impure (7)
17 Batty place where high tolls may be expected? (6)
19 Gemstone set in rubbery leather (5)
21 Marbles man — Nigel, possibly (5)
22 Resident in Highlands cottage? (4)