Reastie glad the tip about the music worked. Unfortunately I use the secret site so there is no option to increase the music - if I turn the TV volume up, the contrast between the coaches speaking and the music stays the same but I just have Dan and Rach shouting at me 
Core de force - I don't know them all that well yet to be able to refer to them by name but the majority of them do not have any plank work in them so you will be absolutely fine. Avoid Dynamic strength and whatever the specific core one is (can't remember what it is called). All the others follow this format:
3 minute rounds which consist of 60 secs of combat work (various combos of punches, kicks, knees etc at your own pace), 30 secs 'cardio spike' (high knee runs, squat jumps, lunges, high jumps etc) then you repeat both then the bell rings and you get a short break. The number of rounds in each workout depends on the length of the workout so the 25 minute ones have 6 rounds, the 40 minute ones have 9 rounds and the 50 minute ones have 12 rounds (these ones are really hard!)
So, a couple of them have cardio spikes that are plank-based (ground to fighter stance which is basically a burpee but you come into a fighter stance at the top and also alternating spiderman lunges - these are the only 2 I can think of and I have done most of the workouts I think). Most of the cardio spikes are not plank-based and I would say that those that are, you can just substitute any form of high intensity cardio move that you want to do instead - you don't have to do what they do. As long as you do 30 seconds of a cardio move, then you would still get the same workout - it is just to make your heart rate increase.
Just try one of the shorter ones and see what you think
I bet you will be converted like I have been 
Did Rip'T up this morning and then Clubbercise tonight - holiday is 2 weeks and I have not lost as much weight as I hoped
but I am still better than I would have been had I not done anything 