Stanley Super 80 Range Cooker

Recently had a Stanley Super 80 fitted, it is the one with a wrapround boiler. Seems to be ok but not really heating rads or a lot of hot water. I think this is down to a couple of things but would appreciate input from other boards members.

Range is fitted in a single storey extension in a three storey house, the third floor has the water tank and expansion in a press on that floor.

Range cooker is in the kitchen, flow pipe runs up to single storey attic space, across and then down to cylinder, which seems to be a few inches lower than the Stanley. Return pipe is running across under floor to cylinder. The length of flow pipe is about 27 feet and the return is about 20 feet. Should mention that the pump is on the flow pipe, about 5 feet from the cylinder. Problem is that the system is pitching sometimes and throwing water into the expansion tank. The water is never very hot and the radiators, which are zoned, rarerly get really hot. Trying to heat 4x4ft doubles and hot water using a mix of coal and seasoned logs.

My thinking is that the cylinder needs to be moved above the Stanley but not too sure then how to reconnect to rads. Any help on a redesign most welcome.