There isn’t a roach alive that won’t eat maggots. Try using a single grub for small roach, stepping up to two or three for bigger fish. Regular feeding is key to building up a good catch – a dozen maggots every 30 seconds is a good starting point.
I clean mine in fresh maize flour and boost them with a few drops of pineapple flavour the night before fishing.
To sort out a bigger stamp of roach, try using red maggots or a bunch of dead maggots hard on the bottom. Being less visible, these baits will be less likely to be picked off by small fish, which feed mainly by sight.