Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
Firstly advise Companies House of her cessation as a director on a Form TM01, you can obtain a blank from Companies House.
Directors are not normally liable for the Corporation Tax (CT) assessments against the Company; it is the company which has the liability not the directors or the shareholders.
The fact that she received 12K worth of training was presumably approved by the directors. Unless she signed a waiver requiring reimbursement to the company within a set period after the end of the training then any recovery action will almost certainly fail. If she has company equipment, you indicate that she has a computer, then that remains the property of the company and she must return it. However, the costs of recovery will probably outweigh its value should she decline to co-operate. .
These sort of things occur with regrettable frequency unfortunately. I am so sorry to have to rain on your parade.
Directors rarely and shareholders never; they are not responsible for a company's CT bills. However, if the company has committed a fraudulent preference ie paying creditors at the expense of another then directors may be held liable for the infringement. Drawing dividends if CT was due and the company insufficient funds is a classic example of a fraudulent preference.
You say that there is not sufficient funds in the business to meet the CT bill then you will either have to negotiate with HMRC to arrange an acceptable repayment schedule or possibly loan the company sufficient funds to meet the bill. However, if directors are aware of an inability to meet current creditors they have a legal duty to call in a receiver to have the company wound up.
Thank you for your support.