Dwightvanman,
From what you've said about your business, it sounds like it would benefit a lot from a dedicated office - ideally, with a shopfront - rather than shared space or a rented room in a business cenre.
With a visible presence in an area like Bruntsfield / Morningside / Newington, there's no doubt that you'd get a lot of off-the-street trade. That alone might justify the higher costs involved. Also, it would look much more professional than shared space or working from home.
That said, you might find that the off-the-street trade might actually be a disadvantage. You might get a lot of time-wasters. It depends a lot on the layout and design of your premises, and how you present yourselves.
I'm not saying that a dedicated office is necessarily better than shared space in a business centre. The latter would be more flexibile and would have a lower initial cost. I'm just saying that a dedicated office would have some valuable advantages of its own.
Mike