I currently have BT Infinity 1 and get about 41Mbps download speed and 6 Mbps upload which is okay for my day to day needs at present. However as part of a retention offer a couple of years ago I was offered an upgrade to BT Infinity 2. When the changeover was implemented from Infinity 1 to Infinity 2 I didn't get any performance improvement. No explanation was offered but BT returned me to Infinity 1 and gave me a price reduction instead.
Last Autumn we had a BT line fault which initially took the phone service and then the internet connection. Took ages to fix and eventually a BT Boost engineer came out to get me back to my pre-fault internet connection speeds. The engineer said that as I live on a 1960's built housing estate some of the BT cabling between the Fibre Cabinet and my house was aluminium not copper as it was cheaper and more readily available at the time the estate was cabled. He suggested aluminium cabling and FTTC didn't work that well together.
My question to those forum members who understand the technicalities better than I do is whether it is true that aluminium cabling between the Cabinet and my house will restrict the service I can get and is it the case that I have reached a plateau which won't improve unless re-cabling takes place?