Grooming Question

[Magnus]

I got referred to this couple that runs a grooming service in their home so I decided to check it out. It's in their basement and they have 5 dogs of their home. Their facility looked decent and mostly, they seemed like dog loving ppl too so I decided to give them a try.

I got a call about 3 hours later from the groomer saying Magnus was acting out too much to groom. Went over and he explained that Magnus does fine being touched but everytime he sees a "tool", he starts barking and biting. It's worse around the mouth area.

I've been trying to prep him for a while by brushing him regularly so I do know he has a tendency to bite on the brush but he never barked or anything like that. He's been to a groomer at petsmart for trimming around the face, genitals, nails clipped. When I asked if he was any trouble, the assistant just said he tried biting alot while being brushed around the mouth. To be honest, I didn't feel too comfortable with the groomers there. Mostly seemed like they were only there b/c they had to.

Is there anything I can do to make my puppy be more cooperative to this new groomer? They seem really nice and want what's best for the puppy. They didn't want the puppy to stress too much and have a bad experience. He suggested I drop him off some time next week and get Magnus to be more comfortable around him.

Any ideas/suggestions would be much appreciated.