Waste pipe plumbing

[Hibbo]

Hi plumbers! Hopefully someone can give me some advice here. Basically, can I do away with this?
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This is behind the bog in my bathroom. As you can (hopefully) see, the waste pipe goes out to the right, underneath floor level, but there is this 'riser' coming upwards, with the bog plumbed in to it just above floor level. All this is boxed in at the moment, but when I redo my bathroom I would like to get rid of this boxed-in arrangement.

What is the purpose of this 'riser' or 'stack'? Is it for inspection/rodding? Is it required? Does it have to be so high? If it needs to stay, could I get away with having it a bit lower, so I could just box it in say up to cistern height?

I hope this makes sense, all replies are appreciated.

Thanks.

 

[neds]

Thats your durgo valve. Its your vent so the stack doesn't have to go all the way up to above your roof. It needs to be higher than your highest waste level like your basin. Chances are that is the height which it is currently at.

 

[Hibbo]

Thanks Neds. I should add that this is a flat - the soil stack for the block is outside on the wall and does go right up to the roof level. Do I still need this? Is it needed because there's a fair run of nearly level pipe to the main stack?

I'm guessing the answer is 'yes', so I'm going to have to do some creative carpentry...

 

[Hibbo]

Just done some reading up on these things (gooooooooogle's great int it!) and I guess I'm stuck with it. I should be able to move it, right? If I can move it in to the corner of the room I might be able to get away with just boxing in to the side of the cistern and not have to do it all the way along the wall.