The reason for the delay isn't the ECI DSLAMs themselves, there's no point rolling out to the ECI's until BT are certain that their field engineer equipment is working correctly.
This has already been discussed in greater depth in the
main G.INP thread a few months ago. We already knew there was a problem with some of the field equipment. There's 2 types in use the JDSUs and EXFOs some of which use BCM chips - again that info is all in the other thread.
There is a solution and new f/w has been developed and is being rolled out. When BT have tested its stability, then they will proceed rolling out g.inp to ECI lines.
I'm quite sure that neither field engineers nor EU's would be happy if when called to a line fault, if some of their test equipment wasn't working properly to be able to get info from G.INPed ECI cabs.