Wow Iestyn, I have just read through your program and the reality is that this would kill a Bull Elephant, since your first stated goal was to drop body fat, I would be looking at that first and working a program around that, so I would be working the Beastly Circuits and a power circuit, you will still improve your strength with these methods,I would not worry about the speed work just yet:
Monday: Beastly Circuit Upper Body 2 x Push Pull Tabata Intervals
Tuesday: Cross Training intervals say rowing machine/bike Boxing session
Wednesday: Power circuit Upper Body Push Pull Repeated speed session
Thursday: Cross Training intervals say rowing machine/bike Boxing session
Friday: Beastly Circuit Upper Body Push Pull Tabata Intervals
Saturday: Cross Country Fartlek Run
try something like this for 6 weeks and let me know how you have come along, cheers,
ash