i think to look in to weather the taxi really happend becouse iwould help to establish how reliable the suitcase story is i finding it hard to belive somone wouldent be noticied in a libary if they were humping a suitcase about
i also think its unlikey that she would take a taxi to town then walk to pack a suitcase and go out agian
There isn't any reason to believe the taxi journey in the evening didn't take place - the taxi driver gave all the info.
The bigger questions here are:
a). was the sighting by the school friend definitely on the same day?
b). if so - what time was it?
c). What exactly were Ruth's movements on the day?
We have a fairly good timeline being that she went to Dorking, went to the florists (as the time has been confirmed about midday) and went to the library before getting a taxi at 4pm from the station. But we don't know for sure how long she was at the library for - there's never been a witness, AFAIK, that has confirmed her being in there for a set time. So with that in mind, she could've left at 2pm, gone to collect her case from wherever it was and taken it somewhere else (hence the sighting which some are saying could be around 3pm) gone back to town to the station and got the taxi at 4pm. This would set-up her ruse of the whole Box Hill situation. Then after being dropped off she could've walked / been picked-up by whoever had her suitcase.
Alternatively do we have any witness statements from the taxi driver in the morning? If not then the sighting with her suitcase could have been from the morning, so sort of putting the idea above into an earlier time frame.
There are a number of hours where we don't have any concrete proof of where she was.
The key here really is the time that the witness saw her with the case. But above all it just adds, JMO, that she was helped in making her disappearance.