Stayed a Fri-Sat night at the Skyline - great value for money (helped by the plummeting GBP exchange rate) with EUR67 including tax etc.
As expected, we were upgraded to a runway view club room. Therefore, the EUR67 included more than adequate snacks and self-serve wine during the happy hour, and breakfast for two, in the lounge. ^
It seems that buses 285 and 555 are the best ones between Heathrow Central and Hatton Cross. However, when flying to T5, the GBP4 rip-off fare of the Hoppa seemed nevertheless acceptable to avoid the hassle of getting to Heathrow Central first.