Being a plumber who has just spent 6 hurs today trying to find out what the hell was going on with a jaguar combination boiler as it will not heat the rads but will deliver hot water, i thinkthat i can help you but not with the location of a manual.
After a painstaking process it was found that the water as circulating round the plate heat exchanger instead of the central heating system. This problem points towards the diverter valve, which if you speak to jaguar will be referred to as the pump block for some strange reason.
Sorry do not have the part number.
Richard Wright FreeFlow Pluming Services, November 2007