The second engineer visit didn't improve anything. He did reset the DLM which boosted speed up to 38 Mbps temporarily but it's back to 34.88 now. Apart from that, he said there was nothing that could be done.
I did find out that we are 700m metres from the cabinet, not 100 as I thought. The cabinet is located at the local exchange.
I think I'm flogging a dead horse trying to get anything close to 49 Mbps.
The speed of your connection will vary depending on the distance to the fibre cabinet that serves your house.
We are 450m metres from the cabinet, and get 55 Mbps max. That's why we changed down from Infinity 2 to Infinity 1,
still getting 55 Mbps on a guaranteed 52 Mbps line!
There are loads of distance against speed graphs available online, but why not try: https://availability.samknows.com/broadband/broadband_checker
For our connection this shows:
You are connected to the xxxxx telephone exchange.
Downstream Min: 44.5 Mbps
Downstream Max: 61.8 Mbps
Upstream Min: 12 Mbps
Upstream Max: 18 Mbps
Also, are you using the BT Home Hub range or a 3rd party modem router?
We found that initially Draytek provided better downlink performance then Zyxel better again still!
Results from Sam Knows...
BT FTTC broadband availability
You are connected to the telephone exchange.
Downstream Min: 52 Mbps
Downstream Max: 68.6 Mbps
Upstream Min: 13.1 Mbps
Upstream Max: 19.6 Mbps
I am now getting just over the 48 Mbps minimum guaranteed download speed with 48 to 50. I'm not sure when this happened and it wasn't as a result of any action by me. Maybe some wires have been unscrambled somewhere. However, I'm not complaining.