Please help. I have new beadboard panels installed in my kitchen. I wanted them to look natural and wanted only polyurethane put on them. The painter came in rolled it on and then used a paint brush to smooth it out. There doesn't seem to be any poly in grooves on a lot of the panels. He says it is done and that it is just the difference in the grain of the wood. I feel that he didn't pay enough attention to get it into the grooves. Pics won't show all this. He seemed defensive about the whole thing and I am upset. What is the proper way to apply clearcoat to beadboard?

Many thanks. I can't afford to pay another painter.