@toadoftoadhall That's interesting to hear. Do you work in the travel industry? I agree that both of those are possible, but the guy at the consulate did seem pretty confident about what he said (I did rephrase the question a couple of times just to clarify things, and each time he told me that a tour wasn't necessary). He also said that I wouldn't need a visa authorisation code, if I knew some Iranians and was staying with them, but otherwise I would probably have to get the code via a travel agent.
I tried Touran Zamin, but they said that they weren't aware of the change. The guy at the consulate seemed to think that once I had the code, it would be relatively straightforward, but I am wondering if either the process of getting a code somehow requires the agents to put me on a tour, in order to get it. Either that or they are unaware of the change...or there is some truth in this 'conspiracy of travel agents' idea.
I know that a few months ago somebody listed an agency that was willing to give a code on its own, without you buying a tour. Does anyone remember the link?
@Gerard.Butler
I'm also planning on going to Turkmenistan afterwards, probably in September or October and slightly concerned about dates (I was hoping to maybe extend my stay once I got to Iran), but this would complicate booking a tour of Turkmenistan (not least because Iran is cash-only). I'd also need an Uzbek visa beforehand, in order to apply for the Turkmen one, I think.

