Hi,
Mine was a nikah only case.
But as has been mentioned in the previous posts, if you are going to apply with Nikah only, make sure that you say so on the application forms. Misrepresentation of any kind, i.e, trying to portray it as a Rukhsati might get you in trouble during the process it self, and lead to incessant delays and even refusal.
In my case, we mentioned clearly that we have had a simple Nikah function in Pakistan, and we plan to have the Rukhsati at a later date, i.e, beginning of 2016. In November 2015, I was asked by the LVO to provide proof of continued relationship, any meetings etc, and the plans for the final marriage ceremonies (Rukhsati & Walima)
Since we had already had it planned for March 2016, and had ample proofs for continued relationship, I submitted a detailed reply in November 2015, and upon the receiving of these documents, I was asked to appear for a Re-Medical, and was issued the visa in 30 days from the time of my Re-Medical.
Hope this helps!