It depends how much you want FTTP now.
It might be that it changes in a couple of days, as database updates are finalised.
If not, the most likely explanation is that BT Wholesale doesn't have enough cablelink capacity at your local exchange to offer higher speeds. It might be upgraded in weeks, or months. An ISP which uses a different backhaul network may have higher capacity there already: try Talktalk and Zen (who can use TT backhaul). If they offer you 500M+ then this is probably the explanation.
A less likely explanation is that your area uses ECI OLTs. Last I heard that is only about 50,000 properties - less than 1% of FTTP footprint - and unlikely to be growing. But it's not completely impossible that if there was already an ECI OLT in your head-end exchange, you've been hooked up to a spare port on it.
Personally I have 300/50 and am very happy with it. This is ten times faster, both upload and download, than I had on FTTC. Downloads run at about 40MB/sec and are already faster than the local machine can unpack and install them. I see no point paying more. My main machine is ethernet-cabled up, but higher speeds are also likely to hit bottlenecks in your wifi.
Edited by candlerb (Fri 12-Nov-21 11:05:38)