On our boat the clutches are right next to the companionway so it is possible to remove them single handed. The screws were quite a tight fit/stuck with sealant so I was able to remove the nuts without having to use a screwdriver. I can get to the underside of the clutches by unscrewing a panel in the ceiling of the saloon. You should have a similar panel in your 365GL but I believe on some of the more recent Dufours this panel is held in by mastic which makes it more difficult to remove.
Life is never simple.
When you reinstall the clutches use a silicon sealant not adhesive and loosely refit the clutches and leave for 24 hours before tightening the screws up. You will definitely need to use a screwdriver for this.
Extracting the front screws from the clutch is a bit fiddly as they need to be guided past the lever but they do come out/go back in with a bit of manipulation.