Ms Lynch acted as caregiver for the couple, assisting in their everyday needs and other aspects of their care.
The nature of this relationship, from October 2006 to Mr Allardyce's death in April 2010, was examined by the Health Practitioners Disciplinary Tribunal after the couple bequeathed $315,000 to Ms Lynch.
Two charges were brought by the Professional Conduct Committee (PCC) against Ms Lynch, related to inappropriate and unethical behaviour in accepting the money, and providing nursing services without a practising certificate.
The case hinged on whether Ms Lynch had acted as a professional nurse, or simply cared for them as a close friend.
Two of the Allardyces' three children, twins Alex and Lucy, were called by the PCC to give evidence about Ms Lynch's role in the care of their parents.
In 2009, the couple's wills were changed to increase the total bequest to Ms Lynch from $225,000 to $315,000. Alex Allardyce said he told his father $200,000 was generous, and $300,000 was disproportionate to what other friends were receiving.
Lucy was clear Ms Lynch's services were those of a nurse. Alex said that he did not get the sense Ms Lynch was diagnosing or treating his parents, but said she did provide medical care during the last three months of their lives.
According to the tribunal decision, Ms Lynch became Mr and Mrs Allardyce's caregiver in 2006 when she moved into a property the couple owned next door to their new Wherstead Rd home. Mr Allardyce had discussed with two friends having Ms Lynch provide care in return for reduced rent.
An Aged Care Matters registered nurse, who became involved with the couple in December 2007, also told the tribunal Ms Lynch had said she was paying reduced rent in return for supporting the couple.
While Ms Lynch did not give evidence at the hearing, she submitted an affidavit rejecting this.
She also stated she didn't think she had behaved inappropriately in accepting the money, or had been employed as a nurse for the couple.
Ms Lynch said she had no idea money was being left to her and this was accepted by Alex Allardyce.
Evidence provided by people who knew the couple showed Ms Lynch to be a good friend of them.
Tribunal chairman Bruce Corkill, QC, concluded the care she provided was in line with a surrogate or family member giving caring assistance. This meant she did not need to hold an annual practising certificate.
Both charges against Ms Lynch were dismissed.