I was fully expecting it not to work based on the previous discussion, I took precautions! But the chap in the office did seem pretty confident of the date so fingers crossed for the new year. It will certaily improve my journey in immesurably.
Just to add that I emailed Oyster after my (failed) attempt to touch out using the readers at Harringay and they have reimbursed me the grand sum of £1.30 (I guess this is the difference between the maximum fare and the fare between Old St and Harringay?).
To be honest, I thought the maximum fare you were charged for not touching out was a lot higher, not sure I'd have bothered getting in touch with them otherwise!