A few months ago she went to an independent financial adviser to obtain advice on a mortgage.
'He immediately asked me why on earth I wasn't in the nurses' occupational scheme,' Mrs Cook says.
The explanation was simple - and unedifying. She had been introduced to a salesman for General Portfolio by a colleague who knew the young man as a friend.
'He came round to my house and spent a couple of hours with me. He seemed very competent. He drew up lots of graphs and charts for me,' she says.
'He explained that he was working on a commission-basis and that he was with General Portfolio, but he classed himself as a financial adviser and said he had an obligation to his customers as well,' Mrs Cook adds.
Mrs Cook, 34, who admits she knows little about financial products, promptly signed up. What she did not realise - because the salesman did not tell her - was that she was forfeiting additional benefits such as cover for illness and injury, as well as any future contributions from her employer.
Whether the salesman himself understood the implications of what he was selling is something on which she is uncertain. 'He'd only just started off with General Portfolio,' Mrs Cook says.
She learned from her colleague that he left the company a few months after selling her a personal pension. She has now taken up the matter with General Portfolio.
General Portfolio insists that all members of its sales force are competently trained before being unleashed on the public.
'Consultants undergo a 10- day foundation course and cannot advise clients alone until they achieve a threshold level of competence, which normally takes between four and six months. During that time they are subject to continuous training and written assessment,' a spokeswoman says.
How much of this training is in sales tactics and how much in the financial products themselves is not spelled out by the company.
But what is obvious is that few people could reasonably be expected to grasp the full complexities of the pensions business within six months.
General Portfolio adds: 'In 1988, we introduced a scheme analysis service to ensure that clients were not wrongly advised to contract out of occupational pension schemes; nearly all clients were advised to remain in their scheme.
'As a result, in 1990, we issued a written instruction that we would not accept a personal pension application for an employee who had opted out of a company pension scheme.
'These instructions have remained unchanged since 1990.'
Yet Mrs Cook says that she was advised to opt out of her occupational scheme in 1991 - and that the company itself took on her business.