The lower/centre bolt (14mm ea) was easy enough to remove with a ratchet. Due to the massive, leaky, hole-filled weld, the right-hand bolt took a spanner. The left-hand proved to be totally inaccessible.
The radiator hose was almost empty so I went to grab my Samco hose set; yes, identified, I can see that this gets replaced. So I cut the plastic clip holding some electric wire to it with scissors.
I contemplated removing the fans to help access the manifold/downpipe base, but the 4 bolts were no more accessible now, so I decided to mull it over, and move back up to the top of the vehicle. As I couldn't move on with the WikiLEC instructions by rote, I thought I'd just start removing un-structural stuff.
Started with the air hose, loosening the two blue-marked jubilee clips. As I loosened the right, the assembly seperated from the air filter box at the junction marked with the orange arrow. Something to ponder for future, as was the fact the air filter box is rocking loose, the bolts just holding. I presume thats wrong, its got to be, but access again was going to be something I would have to revisit after I removed more hoses.
So for now, I shoved it back onto the airbox, and sealed it off with a plastic bag and a rubber band.

- Orange arrow shows previously hidden oil pipe retaining bolt
At this stage, I applied WD40 to every bolt it looked like I would need to undo. The blue-marked bolt is one of a pair - you can see the one to the right of it is snapped right out of the thread. I want this shield off to clean and spray, but its not moving. (10mm)
So by this point, it was pushing 3pm, and light was obviously fading. Panic set in. Was I going to get anything real done today?
I tried everything on the bottom of the manifold and on the top bolt; spanners, spanners with hammers, all the socket bits I had, nothing could get enough purchase. I tried to use an angle-grinder to cut the exhaust so maybe I could get access to the final bolt, but there wasn't enough room to cut right the way through, and hacksaw ditto.
To try and get some perspective, I started loosening other bolts as marked above, and yeah they took force but they were coming. But I didn't see how I could possibly get the turbo out without detaching it from the downpipe/manifold assembly; leaving the whole exhaust connected to it there's no way I would want to just keep removing bolts until something shears off or bends a bracket.....
Eventually I had a brainwave - I ran across to the garage over the road and borrowed some 14mm sockets of varying sizes, from them. With a 3/8" 14mm slim max depth socket, hammered on with a 3/8" extension bar, then hammering sideways into the weld to push the exhaust away, then a jump-up adaptor fitted, then a 12" breaker bar, using a hammer, I was getting about 1/8 of a turn. Rinse repeat, never give up, and I finally managed to crack it.
I grabbed a headlight and pushed on. Eventually, 6 hours after starting, the bottom of the exhaust came away from the manifold. I don't mind swearing I was f**king elated.
I still can't get the exhaust out; I need to break it in half where it cuts over the centre strap - i.e. where it should be gasketed not badly welded.
But as I tidied up and celebrated with a beer, one final thing hit me - I have an impact screwdriver. 5 minutes later; that bolt marked in blue above was loosened.
*****
As soon as I get the exhaust out next session, I will hopefully either be able to access the bottom of the turbo oil feed pipe where it meets the engine block, or to access more of the old cast downpipe to improve access.
Once the exhaust and that bolt is out, I can continue to follow the WikiLEC instructions, and get my turbo out, or spray the underside.
I have to say the terminology is confusing me and I am not 100% on the turbo removal steps. I have shown what I have below and the order I plan to do it. Any help gratefully appreciated; the first issue I have is related to the manual pages shown below:
As far as I can understand it, items 21-24 are the turbo oil pipe but I see nothing which relates to what is shown in (1) below.
1) (Red) I am struggling to work out what this part is. As far as I can see, 2 (blue, which I have already removed the bolt to top and the retaining bolt as it works its way down to the engine block front) is the turbo oil pipe. So what is 1, and how do I safely remove it?
2) (Blue) Any idea what the size of the heavily corroded banjo bolt mounting this to the engine is? Removal tips?
3) (Green) Once these are sorted, I plan to try to disconnect as much of the downpipe/manifold section as possible, working from the bottom up to the green line; which denotes where the new Piper downpipe replaces old equipment; to the right is the OEM turbo which I am porting. The items shown in purple will remain attached and this should hold the downpipe section and be the final thing to remove.... Once all the green bolts (3) are seperated (I have the first 2 broken loose, the back one is going to need some kind of assistance), the turbo will then be seperated from the downpipe as far as I get it. I'm not 100% what support it will then have.
4) (Purple) Assuming the turbo still has support from underlying brackets, at this stage, I plan to remove the bracket held by the 3 bolts denoted in (4), letting the final part of the old cast manifold loose. This will aid in exposing the best access to the turbo for safe removal.
Please do comment as this is the critical bit for me; I don't have a winch to hold the turbo's weight so I am very keen to make the removal as safe as possible.