I am on the 55/10 product but my download speed appears to be capped at 40 Mbps. I believe the capping is at Plusnet's end because the BT speedtester shows an IP profile of 45.07 Mbps and I am synced to the cabinet at 46.6 Mbps. Yet every speedtest maxes out at 38 Mbps download.
My upstream IP profile as reported by BT is 10 Mbps. I think this confirms the 55/10 product.
The strange thing is, after the initial switch to 55/10 (many months ago), I was achieving max download (which is about 45 Mbps for me). I hadn't checked for a while but at some point it has been capped to 40. I think I have seen a couple of other posts reporting something similar on a particular date (in September possibly). Perhaps this is related.
I would be grateful if someone from PlusNet could look into this.