Is there where the resting water level would be in the trap?

[WaterTight]

Red arrow..

 

[Roger Welton]

yes

 

[jonnyswamp]

As above, but it looks like the trap has been modified or the middle part of it has been turned around so the outlet is inline with the waste pipe
As it is the pipe from the half bowl is always full of water
Does it work OK

 

[rpm]

Red arrow..

View attachment 26453

Not sure I`d want to taste the Tonic water!

 

[WaterTight]

As above, but it looks like the trap has been modified or the middle part of it has been turned around so the outlet is inline with the waste pipe
As it is the pipe from the half bowl is always full of water
Does it work OK

It doesn't drain well and initially I thought pipework arrangement to blame but on looking at it I can't really say that's at fault necessarily. It could have been done better but the clipped pipe running along the back is at a fall and so I'm changing my verdict to just blocked and will be taking apart and clearing out.

The initial question was just to confirm my thought process...