Help please - Autocruise Starspirit 2007 (pre Swift). Sink in bathroom is attached to swing wall which is hollow. Waste water from sink suddenly escaped onto floor (luckily shower tray) . I suspected waste pipe becoming detached from sink waste drain plug hole. Took off false pedestal and found waste pipe detached as suspected. But it was now too short to reach sink plug hole by 2-3 inches. The pipe goes into hollow swing wall and out under floor where there is no sign of movement. Pulled on it at entry to swing wall but no slack available. Why is it now too short and how do I remedy other than insert a connecting pipe to fill the shortfall? Thanks for any help.