OK so, I've removed the glow plugs, I didn't reassemble anything (wether that makes any difference or not don't know, turned the key and the engine turn for about a second then just stops like the battery is dead when I know it isnt, checked for any water at the plug holes and nothing, those holes are bloody tiny though

So, is there anything else I should try while I have it in peaces?

Put a bayeery straight to the starter and got at least 1 complete turn of the engine all be it very slowly