The £50 off on a £500 spend is back.
Even though the Terms & Conditions state that it is not to be used for iphone purchases, this is not strictly applied in stores (talking from my experience and many others who have had success).
I ordered my iphone online for collection in store. Then when I went to collect I told them that I want to use the discount code and the staff refunded and reordered. I also used my company discount through vouchers. Unfortunately I only managed to use £30 off £300 spend (as I had not saved the £50 offer before it was pulled off!).
The iphone 6 plus came not only sim free but also unlocked (used 3 sim first to be sure and was able to use EE without any problem and also later changed back to 3. I had to be absolutely sure :) ).
The expiry is in 3 weeks (does not show the exact date though)
So all the best. It is a good 10% saving upfront for any purchase above £500 and not only the overly expensive apple products :)