I can’t find any reference to a point marked IAF of the plates?
Anyhow, I did a lovely short trip today, Southend airport to London City airport, night time flight, GPS course with ILS approach and it all worked 100%, yes the ILS legs do self-activate in the Cessna 172 G1000, a lovely system.
I did mess up by using ATC and then landing with ILS on a different runway but i’ll take that as a rookie error 
and yes, I do take the approach way down before disconnecting the AP but hey, I paid for the system so I’m gonna use it, right