This is one of the hotels which recommends you take the abysmal Hotel Hoppa service to/from the airport, which I certainly would not rely on if timing was tight.

I am not positive about this but I think the road it is on does not have TfL bus service, you'd need to walk to the A4. It's hard to tell for sure from the chart http://www.heathrowairport.com/asset...d_Heathrow.pdf