2. In an ideal world you would want natural links

This is what any search engine optimisation expert would want to achieve, however, this can be difficult.

Possibilities to attract natural links, however, this is likely to take a very long time:

Honesty

Regardless what type of site you have, it is always going to be beneficial if you are honest.  For example, in an ecommerce store: do not mislead a potential customer with an offer that is not what you have advertised on another section of your website.

Additional resources

Providing additional links or tools with your customers is going to be worthwhile, whether it be from them linking back to you or by word of mouth.

Create fresh, interesting content

Keep your customers up to date with the latest news in your industry (in this case SEO Glasgow) or related news headlines.  Anything that is going to be useful for your audience; possibly your business was advertising at an exhibition, write about the day, add some photos to the article and publish it.

Have a presence on social platforms

If possible, be as active as you can on forums and other related blogs, although most of these tend to allow no-follow links, it can still be of value to your site.