Looking at getting a DVB-T Tuner for my TVIX box and not sure which will work and what optiosn it gives me.

I have a M4100 and a M4000.
I thought the T431 was the device I needed but these seem to be rather rare at present or heavily priced.
There is now the T441 which seems to be listed as appropriate for the 6500 but the firmware for the M4100 seems to suggest that support for it is no there or is added in latest Beta.

If I get a T431 does that do HD Freeview for the UK, or just normal Freeview?
If I get a T441 will it work in either? Will it give Dual tuner or just Single Tuner? Does it do HD Freeview in the UK?

Thanks in advance,
Andy