4 across (8) ?M?A?T?D. Affected by strike in which troublemaker took part. 17 across (13) I?E?A?E?T?C?L. Somehow heal it with apt cure having beneficial effect. Looks like an anagram of "heal it apt cure" - first letter-i - might be wrong!
Many thanks, dannyk13 and Oldred. Now, out with the Tippex to correct the wrong solution containing the "i". I had "circular" for 16 down- it should be "stickler"!