We would really appreciate some help with 7d. We have the theme and all the other entries but we cannot see the 3 letter word which needs replacing with another 3 letter word. Thanks
The answer to the clue has a four-letter word, adjective meaning 'limping', plus a letter coming from the 'start of race'. That word is an 'enthusiastic American competitor', though I'd probably have thought it was a UK word too.
The three letter word we needed is not in Chambers as a synonym. We only knew it as as a collective noun which is why we thought we were perhaps looking for a 4 letter substitution. As you say - could as easily been an English word for the original answer.
Bandj, you're not thinking of a word like metallic fabric for limping, as I was stuck doing, are you? There is another curiously similar word meaning limping that applies here.