How to remove 484 exhaust manifold? (picture)

I've just started stripping my 484 (D179 engine) down in order to replace the sleeves/pistons this weekend. I've come to remove the exhaust manifold and 5 of the six nuts/studs came out easily, but the top middle nut is very difficult to get to.

The problem is that there is another manifold between the exhaust manifold and the cylinder head (which seems to be where the cooling water enters/exits the head). I can get 3 of the 4 bolts off this, but again the last one is VERY difficult to get to.

So I'm a bit stuck. Any ideas? I could simply cut the top hose off and leave the exhaust manifold on, but that may not be the best way to go.

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Just out of interest, how many hours on your 484 and what problems is it having that you require replacing sleeves/pistons ?

My brother has a 454D with same engine with well over 10,000 hrs and no problems other than a couple of water pumps and cup seals on input shaft to injector pump.

Good Luck, let us know how your work progresses.
JB

Well I got it sorted. I found a cranked ring spanner that allowed me to get the last exhaust manifold nut off and then the water exit manifold. It was suffering from excessive crankcase breathing and poor starting, but according to the (working) hour meter it's only done 3600 hours.
Having taken the head off this evening we found some deposits in #2 inlet manifold and scoring on #2 sleeve, so one of the rings must have broken. Not got sleeves out yet so time will tell.
I'm going to grind the valves in and replace the stem seals and hopefully that will do the trick. It only gets used for mowing about 5 acres so it's not heavily used - I just wanted to fix the breathing/dripping oil.

JB