S350 intermittent starting fault

[Craigyboy123]

I have a 2011 S350 bluetec with an intermittent starting fault........engine cold or hot makes no difference, key in ignition, turn, message comes up that esp and tyre pressure monitor inop etc, symptoms of a flat battery I take that as, but the battery is brand new, noticed when these warnings come up, the glow plug light doesn't light up, so won't crank over, when the fault occurs when the engine is hot, also the temp gauge sits at zero, won't crank over, how ever, especially in a morning if put my boost pack on the battery, give it 2 mins generally it will crank and start, but I have checked the battery before I boosted it and it was 12.4 volts, so not flat, I have tried a temp sensor to rule it out,made no difference, when the engine is hot, if I let it cool down for an hour it will then start, but that doesn't match the part of in a morning when it is completely cold that it also plays up? Anyone else had this fault????