I agree with elaine.e just ask the groomer to tidy up his feet, make it absolutely clear that she is not to touch the rest of him under any circumstances.
When we got Morgan I was very determined that he would retain his natural silky coat if at all possible and at about the age of Finn started doing the rounds of local groomers, asking for foot trimming only and quizzing them a bit too. It gave me the opportunity to look at their set-up, cleanliness etc. too.
I was dismayed at what I found. Some wouldn't allow an appt just to tidy his feet and wanted me to book him in for bath and full grooming. Some didn't actually have a very nice manner so we didn't ever go back there. The one we went to eventually was rather nice but when I asked about future handstripping her reply was that she didn't do it, she does loads of cockers and they're all clipped quite close because that's what owners end up choosing. I felt her attitude was a bit "like it or lump it!"