I know that you can record two channels at once if they are on the same transponder and then record a third thing from another transponder, but how many simultaneous recordings will the box allow? Would the following be possible?

Recording on Input 1:
BBC 1 London
BBC 2 England
BBC 3
Channel 5

Recording on Input 2:
Chart Show TV
The Vault
Bliss
Dance Nation

These channels are all on the same transponder s as each other on the inputs so could the box really record 8 things at once, not that that situation would ever arise, but pretty impressive if it can.

Not 8 things only 4, each tuner can demux two channels at the same time from the same transponder so the max is 4 from two transponders or just one.

The German cousin of the hdr the icord can do just this

The firmware only allows two recordings at once even though the second tuner can also be recording to the time shift buffer.

I also know that after the promised firmware upgrade to allow recording of the time shift buffer you still won't be able to record more than 2 at the same time.

I have an idea that might let you record the buffer after one or both normal recordings have happened, so in effect recording 3 that were transmitted at the same time. No idea if this will work just have to wait and see