You may have seen my earlier posting "1991 605 head gasket gone - DIY or
junk the car?"
Well, I decided on DIY and I'm now beginning to collect bits of engine
all over the garage floor...

So - first problem for your assistance (there will be many more, I'm sure):

Spec: 605 SLi, 1998cc, injection, 8 valve, XU10 RFZ engine

How to detach the exhaust manifold from the exhaust front pipe?

Exhaust attaches to manifold at rear of engine. (or rear side as its
transverse, but you know what I mean)
There is about a two inch gap between the engine and the bulk-head. The
 exhaust manifold bolts are too rusty to remove, and there's not enough
room back there to swing a spanner anyway. So obvious thing to do is
leave the manifold on the head and detach the exhaust front pipe.
Manifold is attached to exhaust front pipe via a big flange and two
sprung bolts. Not a simple nut-and-bolt arrangement, there are these
spring things. Impossible to attack it from above as there's so little
room behind the engine. Impossible to get to it from below as there's
all kinds of suspension and cross-beams in the way. Apparently (I'm
guessing) Peugeot saw the problem, and fitted these sprung bolts which
fit into slots (not holes) on the manifold side - some kind of
quick-release mechansim, but I'm stuffed if I can figure out how to
release the front pipe from the manifold.

I know there any not many 605s in the world, but anybody out there got
one and done this ?

Dave, Winchester, UK