Hello again. It is non-ECC memory and it complies with all the descriptions both I and hellsbrink have been able to find except this damned high density/low density business which has been previously unknown to me.
I doubt that one module on its own would respond any more than the one which didn't respond when paired with an original - unless you know different?
Got an email from the seller who wants any return sent via tracked package - he spent just over £1 mailing to me but charged £8 p&p and I bet he won't refund any of that !