I didn't want to hi-jack the other thread about Iranian visa's but i thought i'd let those waiting for this visa know of my success.
I hadn't realised that Iran had the unusual New Year so my application was delayed while that period lasted, so i was nervous since i had planned to leave the UK on 1st May. I used Magic Carpet following a recommendation, and the application left their office on April 10th which would have been a weekend day i think in Iran.
The good news is i received an email this morning with my authorization number and i now have one month in which to pick up my visa in Istanbul. I had chosen the Istanbul pick up as i thought it would take much longer to get, if i got it at all, but i could have got it in London with time to spare as it turns out.
Hopefully this will give some cheer to anyone waiting.