The real question is, do you need a consultant for evaluation of suppliers. New ISO 9001:2015 is very clear on what needs to be done in order to conduct effective evaluation of suppliers.
First you need to establish criteria for evaluation, selection and monitoring suppliers. This means that you need to determine what is really important to you when it comes to selection of the suppliers, criteria can be the price of products and services to be delivered, the quality, shipment timing, etc. Different criteria can have different importance to you, so you can assign different scale to different criteria to demonstrate their importance and to help you make better selection. Once you define criteria for evaluation, you need to determine criteria for selection, meaning how high on the scale the supplier need to be in order to be selected.
When you determine criteria for evaluation and selection of the suppliers, next step is to conduct t he evaluation and select the suppliers, as a result of this activity you will have a list of approved suppliers, and this evaluation needs to be conducted periodically, usually every year.
Keep in mind that the new version of the standard treats the same the suppliers and outsourcing partners, so you need to include in your evaluation not just the your suppliers but also outsourcing partners.