Here is the progress I am making on the outer shell of the gherkin. As you can see, there are no tricks everything there is modelled and I am currently working with 43,000 polys.
I forgot to post some more research that I got. Since the creators of the gherkin won't send out blueprints, I came across the book '30 St Mary Axe, a tower for london' which has a lot of detailed information about the building and a lot of detailed images that I could not acquire any time soon.