Hi
I agree with Colin, I think his advice is sound.
However, I do not think that you can register Diva as it is a term generally used as a description and not unique to you in any way. You could possably register "Diva Tanning" as this is specific. It will cost you £100 to submit your application, with no guarantee of sucess or refund. An example of this is a product that we import, we could not register "PFB Vanish" because "PFB" is a medical term that is widely used. We the tried to register the logo which was denied for the same reason. This cost us £200 for these applications with no result. There is however some protection in law for prior and pre existing use..this however would require solicitors and lots of money as stated previously.
We recently had a dispute with another company using our company name and registered trade mark in adverts, despite it being nothing to do with their trading name and having the registration was invaluable stopping this.
Companies, when starting out, should select a unique name and register it immediatly to prevent others passing off and stealing your businesses goodwill