High level to low level cistern

[nealbyuk]

Just been asked to sort problem with a toilet. I want to use high level cistern 9 litre (existing) and drop it to a low level. First thoughts are oversplash but are there any other concerns I should have? I want to drop cistern by about a metre to metre and a half.
Problems:-

Horizontal waste at back of WC ( S Trap )
New low level toilets with S trap are usually only 4 litre from twyfords
This guy is 22 stone so 4 litre definitely won't do even 6 litre is not enough in my opinion. Hence wanting to use the 9 litre.
He needs a pneumatic button valve because he wants the cistern boxed in and doesn't want a lever.

 

[samtheplumber]

shouldn't think there will be a problem with over splashing!. what do you mean there is problem because of the 's' trapped pan?

 

[nealbyuk]

the problem is finding an s trapped close coupled cistern with enough water in it to clear a pan thats gonna be running at full bore ( remember he's not a small bloke) and I can only find a twyfords toilet to fit the bill ( 4L) which I don't think will be good enough. I know I can adapt a wall exit trap but with close coupled that generally means they sit off the wall which looks a bit bodged. He doesn't want to buy a new toilet and then have to box it in.He only wants to box in if he has to keep the existing cistern because it does look a bit shabby.

 

[Steve001]

I'm sure six litres will shift the heaviest of jobs, not be easier cheaper to buy new cistern/bog? Or am I missing something? Pan connectors.. is that what your having bother with? I'm gonna shut up and stand asside.

 

[samtheplumber]

does it have to be close coupled? can you not get a six ltr wall hung cistern with a flush cone? and then box around that? or if there is enough space behind the pan use a flexable pan connector to bring it back to the wall if possible.

 

[nealbyuk]

Sorry lads I didn't explain very well.Uncle has high level toilet works perfect and pan looks fine but the missus wants room done up and everything matching etc etc.. Cistern is black plastic and pan is white and she doesn't like the cistern(downstairs toilet with floor exit waste in very small room).
Idea was to drop cistern and box it in plus put pneumatic valve in because she wants a button. I just wanted advice to see if anyone had experienced problems when cistern was lowered in terms of flush.
If there was problems doing it they would have bought new toilet but interested in close coupled only. Can only find one type of toilet which replaces like for like waste but its only 4L. Did anyone know of any others? Only other option is to buy 6L close coupled and adapt the waste.
When I said I had a problem with a toilet it was deciding whether to bother with the new toilet and possible pan connector or just use existing. You've already given me the answer which is that there will be no problem with flush so will drop existing cistern and change valve for them. Better flush, no shopping around and cheaper for them which ticks all the boxes.Cheers