I've noticed you have also the ER-4S. Any reasons why you chose that model instead of ER-4PT?
I think ER-4PT is the model i'm leaning to since it is far cheaper in amazon.co.uk than ER-4S. And you can get the two year warranty from amazon.
PT was not available at the time I bought my 4S. I've had them for over 10yr.
p.s. and if they were available, I certainly can't remember