I used to have it on my Toppy, the data is pulled from the BBC and merged into the EPG via MyStuff.
I stopped using it because of the memory limitations on the 5810 model as opposed to the 5800 version. It was really good, as well as the 14 days of data you could actually read more in depth Radio Times reviews.
I don't really miss it TBH.
Put a reminder in your iPhone calendar. That's what do, . Unless your not at home, and if not, then there's always the RS-WebIF