Can I adjust the in/out water temperature settings on Ideal Classic FF370?

My Ideal Classic FF370 boiler (about 10 yrs old) is behaving a little oddly. When everything is fully up to temperature the gas shuts down, as it should. As the pump continues to operate and pump water round the system the gas then refires, almost immediately and it continues on in this fashion. Sometimes the gas valve opens and shuits again even before the pilot light kicks in. It feels like there should be a controller to change the water temperature differential between switching the gas off and back on again when at operating temperature. Can anyone help?