Long-term work with the site on the platform 1C Bitrix

We are looking for a company that will be engaged in the development and promotion of our online spare parts store on a long-term basis. The site is on the 1C Bitrix platform, but a large number of functionality was finalized.
To start cooperation, it is necessary to conduct an audit of the site and report on it, so that we understand that you have estimated the amount of work, identified problems, understand what you will have to work with, and are ready to provide quality services on a long-term basis.
The staff must be: developer 1C-Bitrix, developer 1C, server administrator, seo-specialist.
Site link: ati-auto.ru/