Yes, I have been caught in that trap.
My upload dropped from c. 12.5 Mbps throughput to 9.3, and my download is stubbornly stuck at 37.3 with a max attainable from BT Wholesale speedtester of 46.86.
PN telephone support yesterday first cut me off after 15 minutes, then on second call said they were aware and the problem would be fixed in 4 hours (i.e. c. 16.00) and i should reboot my router.
Today, no fix, support first told me the change wasn't due to happen until next month (!). When challenged, they admitted it was and they were confusing it with the price changes.
Now the fix for the 55/10 capping problem is not due to be fixed for another 24 hours, or possibly 48.
I'll just await events.
Not especially happy at the moment.