Hi Gitto, 23 : backwards, (L)am (US for runner), ex; 7D EPO is a haemocyte hormone taken by sports cheats; 15 is a US slang word for money, just put A in a 4-letter word for a thing you bake in (and leave out an N.
There are 9 clues with extra words, giving 18 letters. So, as DJA said, if you've deduced what's going on so far, think of how 3 of those letters aren't going to feature in what is written below the grid. Technically this should probably begin with a hyphen.
Hi Notrab, I hope that the above para is a help to you too.