@td47 Many thanks for replying. I am sort of accepting these limitations, just needed to make sure it wasn't me doing something wrong.
I am a software developer with 30+ years of experience in real-time systems and such so I believe I can have a pretty good guess how this works. It really looks to me that they haven't made the effort of spending a bit of time to improve it. According to the specs the hardware should very happily support recording a stream for live pause / separately from the recording, and maybe have a third stream for the other tuner. If a £100 box can do that I am pretty sure a £2000+ equipment is able to do that too. And it is Linux based, so pretty standard really.
I just hope that LG reads this forum and takes this as a feedback.
Nic.