UK Bands on the M6 Pro

[Watson306]

Hi Guys,
I am new here, but I was close to buying a MR6500 from the US – I am in the UK, and the generic model here is the MR6450.
But at the last minute I had this gut feeling about the bands supported and I looked into it and they're not similar at all.
The thing is the US version is significantly cheaper than the UK version.
Is it possible to add bands to the MR6400?

Thanks in advance