Firstly, I would have asked your Broadband SP to raise an SFI/SFI2 engineering visit. Most (if not all) SP's are happy to pay for us (as opposed to you paying) to rehash the old PSTN star-wiring of old, into a fashion more suited to DSL transmission. At the end of the day, the SP doesn't want 'Repeat Reports' of any kind on your circuit, just as you dont want 'repeat faults' on the circuit.
Secondly, it is not only in our remit to replace ANY obsolete Master Sockets for the new NTE5's, it is also a 'Quality failure' if we dont. This leads to disciplinary action of we engineers, so he wasn't just 'doing you a favour'. Also, the upgrade of the NTE5 is cost-free ...... unless of course there's obvious damage like a bloody big axe stuck in it.
Yes, the old 'Dropwire 6' (ribbed wire) has a larger poundage than the newer 'Dropwire 10', but for the distance it is used, it will have little or no effect whatsoever on speed. What the newer 'Dropwire 10' will do, is eliminate 'Noise' far,far better than 'Dropwire 6' due to the wiring being twisted pairs, as mentioned by another OP earlier. In other words, the DW10 is more suited to DSL than the DW6.