Before you choose an Accountant, you could ask to see examples of their work, read testimonials and ask to see references of past work they have done.
The AAT (Association of Accounting Technicians) qualification is the minimum level of qualification required for most kinds of accountancy. To become a chartered accountant, you need to obtain higher level qualifications such as the ACA, ACCA or CIMA, which will allow you to become a chartered accountant.
You could also look at their profile page on Bark and view reviews from past customers as well as examples of work that they have completed. This might also help you get some ideas for the types of services you need.