I am starting on my own as a sole trader practicing architecture.

I have chosen to start as a sole trader for a number of reasons,
and will review the structure annually.

I'm currently developing my letterhead and as I am not trading
under my name, I need to say at the bottom who I am trading
as the business name, namely:

scott theobold trading as bold architecture design.

what I am currently unsure about is whether to call myself
a 'principle' or 'director' or not at all.

I will potentially be employing 1 person for admin etc. and may
in addition engage others also.

not sure what the rules are, or any guiding principles?

thanks