hi guys, hoping someone can provide this info for me..

Im replacing the turbos on my 997t engine and having to replace all the lines as they are rusted in and cant be removed (believe me I tried). So I have taken the engine out to address a few jobs while I do that and one of them is to rebond the coolant pipe stubs on the front water manifold. I am having some issues getting pipes with orings out, from pretty much anywhere low down on the engine (uk weather is terrible to these cars) but I need to remove this coolant block/manifold as I want to replace the orings and protector seals under the casings (that go into the pipes that feed the engine) plus do the coolant pipe jbweld and pin. So as far as I can see I have got everything off except the rubber pipes on the top... you got it , they are proving very hard to get off so I may have to stanley knife slit them so I dont damaged the outlets. but anyway I dont seem to have any movement on the water manifold (at the bottom) and I would have expected it to pull away from the orings at the least, am I missing something? Does the bolt I highlighted in the diagram need to come out? I cannot find anything in the engine stripdown pdf I have, I wonder if this coolant manifold is a different document number? Either way. if anyone could confirm I would be very grateful.

*The oil return at the bottom is unclipped from the pipe clip

thanks