The decision to hire a process automation consultant typically follows a moment of epiphany - a realization that manual labor isn't the most efficient way to operate. The thought of transforming your business process for optimal efficiency and productivity is an alluring one. However, there are a few intricate details about process automation consultants that I wish I had known before leaping headfirst into the hiring process.

Firstly, it is paramount to recognize that process automation is not merely about technology. Of course, tools like Robotic Process Automation (RPA) and Artificial Intelligence (AI) play significant roles. However, the essence of process automation lies in reengineering the business process. It's about understanding the ‘why' behind each procedure, dissecting it, and reconstructing it to be more effective. The consultant's role, therefore, is to act as a ‘surgeon,' delicately navigating the complexities of your business processes.

Secondly, the consultant's knowledge and expertise reach far beyond the realm of automation technologies. They need to understand business models, supply chain dynamics, industrial relations, and even a touch of socio-economic factors that influence your specific market. This multidisciplinary expertise is what sets apart a process automation consultant from a mere IT specialist.

Thirdly, process automation and the lean methodology go hand-in-hand. The primary tenet of lean methodology is to eliminate waste, and automation is a tool to achieve that. Hence, a competent consultant should be able to employ lean techniques to identify non-value adding activities, also known as muda, and automate them where possible.

Fourthly, the importance of change management skills cannot be overstated. Automation invariably leads to significant changes in the working environment, and human resistance to change is a well-documented phenomenon in management literature. A proficient consultant should navigate this change adeptly, ensuring that employees transition smoothly from the old process to the new.

Fifthly, the cost of hiring a process automation consultant isn't solely their quoted fee. Consider the indirect costs, such as the expense of training employees on new systems or the temporary productivity slump during the transition period. A cost-benefit analysis is essential before making the decision.

Sixthly, the choice of consultant should also be influenced by the scalability of their proposed solution. Simply put, can the automated process grow with your business? While short-term efficiency gains are important, one must not ignore the long-term flexibility of the solution.

Seventhly, it's important to note that complete automation isn't always the ideal solution. Hybrid models that combine the strengths of human intellect and robotic efficiency often produce the best results. A good consultant will not force a fully automated model if it isn't the best fit for your business.

Eighthly, data security is a non-negotiable aspect. With recent controversies around data breaches, it is crucial your consultant prioritizes data security in their solutions. They must be conversant with regulations, such as the General Data Protection Regulation (GDPR), to ensure compliance.

Lastly, patience is a key virtue in the automation journey. It’s tempting to expect immediate results post-implementation, but realistically, it takes time for the ROI to materialize. The consultant should set fair expectations and not overpromise on immediate outcomes.

In conclusion, hiring a process automation consultant is a meticulously detailed procedure, which requires a deep understanding of your business's needs, the consultant's capabilities, and a reasonable outlook on the post-implementation phase. The decision should never be based on the appeal of cutting-edge technology alone, but on a blend of factors that include process reengineering, change management, and long-term scalability. No one consultant is a perfect fit for all businesses, and hence the importance of a comprehensive evaluation based on these parameters is crucial.