2453: All right?

Unclued lights, five of two words and two pairs, have something in common. Elsewhere, ignore one accent.

Across

1 Keep bearing left for Great Lake (5)
11 Mule is slaughtered for food (6)
12 Delving into information, understands about saving (7, two words
14 800 in circle, enormous (5)
15 In the country, must run at first over mountain (5)
16 Boil may come into view, with light (6)
21 Consume a lot of meat, in total (7, two words)
23 Land in Scotland picked up, not hard (4)
25 Original Dutch tongue (4)
27 A long period in Chinese epic (7)
29 With knife, son carved hairy boot (8)
33 At any point of the compass, a dance (6)
34 Gas attack in progress, it’s said (5)
36 Caught boy on TV without clothes (7)
37 Apple: scientist gets one for nothing (6)
38 Cook priest a gruesome thin broth (10, two words)
39 Examination of slide, most clever to conceal drug (9, two words)
40 Hearts removed from fruit in school (5)

Down

1 Power to replace fourth letter in term for ‘sewer’ (8)
3 Short cloak called upon briefly (6)
4 In sickness, I must get down a little food (7)
5 Move slowly in parts of shoes that should not be submerged (10)
6 Plant that is host to lac, horribly sticky stuff (7)
7 Relax, and stop holding down? (5, two words)
8 Permanent impression nurse made on most of school (8)
9 Wrinkled carpet covers body of mouse (6)
13 Clumsy? Not I, a French god (7)
17 Girl’s swearing about ordinary sermons (10)
18 So long in Sandhurst without electronic product of 34 (7, two words)
19 Fewer than some number for light meal (6)
26 Acquire property as cut up for ploughing (7)
28 Fling heavy stick and leaded glove … (7)
29 … by degrees a way into some trees (6)
31 Bind in honour to suppress party with free drink (6)
32 Company to knock back French wine and soft drink (5)

A first prize of £30 for the first correct solution opened on 4 May.