I rang Sky this evening as my team were playing in a friendly game on ESPN and I'd heard they were doing another free subscription period for the channel.
I thought it might have been one of those typical Sky type offers which you can only get if you're down on their system as having been mailed it but no it's open to everyone as I was given it with no questions asked.
I later kicked myself after realising the offer is listed on the Sky website and I could have got £5 cashback from TCB / Quidco and actually made a profit but nevermind.
Conditions are that you must have or upgrade to Sky Sports and 31 days notice is required for cancellation.
And yes I am already aware that ESPN is bundled inclusively on some rival operators packages.