I have ordered a couple of these 3DR radios from the US (DIYD) which have now been shipped. We will see what customs make of them. Looking at the spec I can only see them tuneable up to 454Mhz but perhaps Tridge can point me in the right direction.
With the 460Mhz band being for short range business radios there are lots of inexpensive antennas available which will be more closely matched than 433Mhz.
Look at page 3.
454 is your max frequency. The PA matching network will filter out anything above this, even if you set the frequency higher in the software.
There is a 470mhz version you could get that tunes 450-490mhz