A woman I manage at work has put in a complaint accusing me of saying that she has bought the company into disrepute, she is now threatening to take this to court.
As in, she's threatening to sue you privately for libel/slander? Ignore her, she is almost certainly not willing to spend the tens-hundreds of thousands of pounds it costs to do so.
Nowhere have I stated this in writing, however as part of her disciplinary interview I did state that her telling clients that she Facebook stalks them, making inappropriate comments to clients (flirting, accusing them of cheating etc) and lying about the work she has yet to do does have potential to harm the company’s reputation and that she is part of the company and should be representing our company. This was undertaken due to 3 separate complaints coming in across two days from 3 clients as well as us uncovering creation of false invoices.
So you have said it, or words to that effect? I wouldn't worry. Assuming what you've said here is accurate, it's a fair statement. Her behavior is unprofessional and is reflecting poorly on the company, to the point of generating multiple complaints (which I assume you can evidence).
It's more than reasonable to tell someone that they are bringing the company into disrepute in those circumstances.
HR have advised that as she’s put in a complaint about me all disciplinary action is now to be paused.
This is normal. I suspect her complaint isn't that you've told her she's bringing the company into disrepute, but that you're somehow bullying/treating her unfairly in the disciplinary process. It's common for people to make such nonsense claims.
She has also now signed off long term sick with anxiety due to this comment and the stress of the disciplinary process.
This is also common.
I just want to know if this has potential to become an issue; is it because she’s accusing me of creating a narrative and reaching a conclusion before the disciplinary process had concluded
How can it? As long as you haven't made these complaints up, or been gossiping around the office about her behavior while you're engaged in a disciplinary process, it's a perfectly reasonable bit of feedback.
If she's made an allegation that - if true - would mean she wasn't getting a fair process, your employer has a duty to investigate this.
She'll have nothing to back her claims up, you will. Nothing to worry about.