mystery leak under bathroom sink --- how to access?

[monkeydance]

Hi,

So I just replaced a leaky city water inlet. (http://www.airforums.com/forums/f443...nt-147045.html)

But apparently that wasn't the only leak. The leak is not coming from either the city water inlet or the no fuss flush inlet/vacuum breaker unit.

I see the cold/hot water lines running along the wall (to/from the hot water tank), and there is a vertical L-shaped connection branching off from that --- I think the leak may be somewhere on the line above that L.

Is that the line that connects to the bathroom sink?

Any suggestions on how best to access? I don't see how to remove any part of the vanity to get a better look...

I can see the back side of the dinette from under the sink, so is the thing to do to remove the dinette back somehow?

Thanks for your help.