Thinking about these calls to the pub the afternoon SJL disappeared, both are intriguing. The one from the supposed police officer makes no sense because why would they get involved in a found cheque book; so I tend to think this was from the killer checking when and where she was expected.
The one from the woman is really interesting because this was apparently from a "Sarah" asking that SJL be kept there until she herself arrived. This was looked into at the time and SJL apparently did not know any Sarah. Could SJL have been meeting a married man that day, whose wife's name was Sarah? Thus SJL knows the man who has edged out AL (and others) is married, and she knows his wife's name is Sarah, and Sarah has worked out who SJL is and where she will be, and Sarah intends to go there and confront her husband's mistress. SJL won't be keen to meet Sarah, neither will her diary contain Sarah's phone number.
Did not AS indicate that SJL had become involved with a married man?
On the Lolly True Crime website (The Suzy Lamplugh Puzzle Part Two), the blogger states she did have a friend called Sarah. Worth noting I guess -
‘Suzy attends a party for her friend’s 21st Birthday near Dorking in Surrey. She’s at work at Sturgis and Sons in the morning, until lunchtime approximately, and later in the evening, about 5pm, is picked up by close friend Sarah, at Suzy’s flat in Disraeli Road, Putney.
She plans to stay the night with Sarah’s parents and seems to have really enjoyed herself at the party, “looking resplendent’ in a new dress. Her friend, celebrating her 21st, is from the same circle of friends and is also an estate agent. Adam is not with Suzy at the party.’