I agree with Jaybee. It's worth finding a good groomer, even if it's only something you resort to occasionally. Also, it's worth getting him used to the experience. As others have said, just be absolutely firm on what you want done and make sure the groomer has experience of cockers. I rejected one groomer in town for Penny because she admitted she'd only shaved cockers before.
I started taking Penny (to a different groomer) when she was about five months just to get her used to it. She just had a bath and her feet tidied. The next time the groomer stripped out some of her puppy fluff, but I made it clear no clippers from the start. The only bits she's had clipped are the insides of her ears (because it helps the air circulation, especially when they're always wet) and her armpits, to avoid the matts caused by her harness. She loves going to the groomers now, and I always specify exactly what I want. I like to handstrip her head myself, and I use the Coat King as well to keep on top of the undercoat, but I'm not confident shaping feathers and doing feet and nails.