sounds like your m8 has a box thats been flashed with 3rd party firmware to allow it to have the sky+ features without having a sly subscription.
this is not a hack for free sky, it just allows you to pause, record, rewind, etc without having to pay for it
if your m8 wants the box back to normal, meaning the sky+ features won work without an active sub, then it MIGHT work by forcing a software update on it, but ive never tried this
disconnect the power, press and hold in the backup button on the front of the receiver, reconnect power, after 10 seconds or so all the lights on the front of the receiver will come on, and itll say onscreen updating software
thisll take aboiut 10 mins, then the box will restart
its possible that this may reflash the box with official software, but as the software on the box at the moment was forced onto it via jtag its more likely that nothing will happen and hes stuck with it
if he wants to swap for a standard sky+ box through the post, let me know m8