There are three different areas of information you need to think about when you take this assessment
The data you process about your staff
The data you process about your customers/prospects/suppliers
The data you process in the products and services you provide.
Many doing this assessment only thought about what they do as a service for example
"I'm a software development company my customers are the data controllers " often missing the data they process about their staff/ & customers.
If you are processing information for the purposes listed below and the ICO Self-Assessment said you don't need a registration, then it’s likely you have gone wrong somewhere along the line and didn't get as far as this list on question 7
Accountancy and auditing e.g., you're an accountant
Administration of justice - including police and probation boards
Administration of membership records
Advertising, marketing, and public relations for others
Charities - including housing associations
Childcare i.e., childminder
Constituency casework
Consultancy and advisory services
Councils
Credit referencing
Crime prevention and prosecution of offenders (including CCTV systems)
Debt administration
Education – including schools
Emergency services - including ambulance and fire service
Financial services and advice
Health administration and provision of patient care - including medico legal, pharmacists, optometrists, and dentists
Insolvency practices
Insurance administration
Journalism, media, and TV / radio stations
Legal services
Loyalty cards
Mortgage/ insurance broking
Pastoral care
Pensions administration
Personal information processed by or obtained from a credit reference agency
Private investigation
Property management - including the selling and/ or letting of property
Recruitment
Research
Social - including networking sites or dating agencies
Software development - including web hosting and design or IT support