EGR Valve - Please help explain mine to me (pics!)

[joropug]

Hoping you guys can help me with a query about my EGR.

Car: 05 1.7cdti Astra

I decided to inspect it today, I'm getting the fairly common P0234 engine boost condition exceeded error. (Overboosting)

I have the following symptoms:
-Occasionally at 70mph ish the spanner light comes on (not engine light) it's usually after acceleration and the first time it happened was when I did a long pull in 5th.
-May not be related, turbo quite loud when letting off from full boost (chatter type sound, just louder than I'd expect)
-May not be related, when engine is cold there is an audible whistle consistent with turbo speed/pressure

I wanted to check the EGR to see if it was stuck open so had a go today.

Used this video for guidance:

https://youtu.be/U_RPAfxvcH0

I'll state at this point I'm pretty clueless with turbo set ups so please feel free to educate me if i say something wrong

I removed the pipe between the intercooler (green) and the EGR (orange) note rear pipe (blue) which the video suggests goes to the inlet manifold:



The EGR itself didn't look too bad. It's open by default, not sure if this is right but the one in the video was too.



The pipe at the back of the EGR however is horrendously coked up (blue arrow in previous):



The green arrow indicates a vertical tube that is clogged up completely from what I could tell, I have no idea where this goes.

So I need help understanding:
-Which direction is the air flowing here?
-I started cleaning the blue arrow pipe but was worried about chunks of sludge being ingested so held fire
-What is the vertical connector that's blocked up?

If I 'blank' the EGR what does this block ?

After reassembly I took it for an Italian tune up and didn't get an error message at all. The engine was cold and I'm sure the turbo whistle I mentioned wasn't as prevalent but could be a coincidence. I didn't really do anything so it's probably short lived.

[finlo]

The variable vanes on your turbo are sooted up, YouTube it for a Mr Muscle quick fix.

[MatrixXXx]

The EGR lets exhaust into the air intake to stop combustion by reducing the oxygen level, it should come off , so you can clean it , there will be a valve somewhere that will be sooted up and not moving.#

if you get a blocking kit it will replace the egr and will have a resistor to fool the ECU into thinking the egr is still fitted.