The unclued lights (two of two words, one of which includes an apostrophe) are of a kind. Where alternative final letters occur, M and O are to be used, not T and I.
 

Across

11    Carpet salesman finished right at the front (7)
12    Rode at front, elevated as aid to driver (6, hyphened)
16    Superior meal, seconds not required (5)
19    Negative terminal coated roughly with touch of hydrochloric (7)
21    Look closely for perimeter of perimeter! (4)
23    African country’s merit reappraised just a little (7)
24    Old coin in Roope’s overcoat (4)
25    Recommend guests get changed around midnight (7)
30    Get stressed and awfully upset about...