is 'taxi driver' classed as a job of a lower socio-economic background?

im applying for a work experience programme targetting socially mobile backgrounds and one question asks if "The occupation of your main household earner when you were aged 14 is categorised as a lower socio-economic background". I live in a single income household, with the income being less than £16,000 a year and my dad is a taxi driver. the social mobility commission's toolkit classifies 'taxi owner' as being a small business owner who employs <20 employees, but my dad doesnt employ anybody, he is an employee of a taxi company. what category do i fall under? am i classed as having a lower socio-economic background?

link to smc toolkit: https://socialmobilityworks.org/wp-content/uploads/2021/07/SMC-Employers-Toolkit_WEB_updated_July2021.pdf

Yes, he's a taxi driver, not a taxi owner, in this context.

of these, which category would that job be?