New Customer - Service not what I expected

[#1]

small child in the house so no time for online games at the moment so please go ahead

[#2]

Don't the router stats imply interleaving is already on?

[#3]

Yes, but there is no interleave depth, which suggests an order to implicitly place it on the line may be worthwhile.

[#4]

It could also suggest that interleaving was in place when you were with Zen, which would explain the intermittency.
I'd definitely suggest giving it a go