Finished this morning when I realised how 19 worked so could add its middle letter, and also suddenly got the wordplay for 8, having already got a swimmer which fitted the crossers.
Looking at the forum explained the previously puzling "number" and " giving off bad smell": a new word learned.
FOI: 1d
LOI: 8d
COD: 17a, though it took a while to spot the parsing for the last letter: clever clue.