Here's both the questiion & the answer.
I was having issues with analogue recordings (from my dual 150MCEs) not fully reocrding. They would stop after a variable amount of time, ranging between 4-20 -odd minutes. I couldn't work it out.
Then I remembered I had changed their priority within the TVServer configuration.
Inside 'TVServers Configuration>TVServers>*hostname*' there is the ability to disable & prioritise the cards' position. I had disabled the analogue tuners in my HVR-2200 -because up until recently they did not work inside MP- & moved my two 150MCE cards up in ranking. Once I moved them back to their original positions, the records behaved properly.
Moral of the story: don't move the cards positions. Now, to test if I can record analogue in mpg instead of ts format.