The 300 meg service was previously capped at 330/21, but there has been a change to the config file and it now runs at 345/21. Probably so they can say it is faster than infinity 4 I guess.
If on the 300 meg service, it's probably worth rebooting.
Not a massive upgrade, but then an extra 15meg would be amazing if I could have it at work!!
Of course single threaded speeds are lower, while still higher than anything I could get on FTTC.