Ev 1493

[hankir]

Both clues have a missing letter in wordplay.

42. Society talk about variable mixture of CO and H (6)
N is missing.

19. West country mining lease argument (5)
O is missing

Thanks

[novalis]

Usual abbreviation for society and a 3 letter word for to talk, natter round Y (variable). Your N is the third letter.
5 letter word for argument (hyphenated 3-2) Your O is the last letter. This one of the eight entered unchanged.

[hankir]

thanks novalis