Crazy but so far on the 1.00(AAKL.7)C0 firmware all looks good this morning:
Average error rates for 17 Jun 2016
CRC erors per hour: 0 Down, 0 Up
FEC erors per hour: 91654 Down, 0.78 Up
HEC erors per hour: 0 Down, 0 Up
ES per hour: 0 Down, 0 Up
SES per hour: 0 Down, 0 Up
There I go tempting fate again!
Speed has come up 1Mbps and interleaving now coming down again, currently at 2517.
I'll leave it as is and see if DLM does it's stuff to bring my speed back.