Final answer:
Gill's wish to have a say in the running of Compugames Ltd can be fulfilled if she invests in the company. Jack can offer her a seat on the company's board of directors as the only shareholder and director.
Step-by-step explanation:
Gill's wish to have a say in the running of the company can be fulfilled if she invests in Compugames Ltd. As the only shareholder and director, Jack has the authority to decide who can have a say in the company. Since Gill is willing to invest £100,000, Jack can offer her a seat on the company's board of directors. This would give Gill the opportunity to participate in decision-making processes and have a say in how the company is run.