I've always found that using blokes on remedial / downgraded as part of the lesson is extremely beneficial to everyone concerned.
After the struggle to tie the biffs to posts is over, the lesson really starts to come together.
Once the initial shock of plunging 8" of cold steel into a living human is overcome everyone will start to get the bloodlust. The bloodcurling screams of your students mixed with the pitiful cries of "the fabloned sick chit" crew emulsifies into a unique concerto.
So, in summary you are killing two birds with one stone - training the deserving soldiers and eliminating the admin cases!
I find using a pleasure and pain area works well. Use the pleasure pen to demo your next action and the pain to keep the momentum of the lesson going. By sending them to the pain pen (where they are put through a physical workout) this gives you time to sort out any of the dummies that may be suffering from the bayonet action.
Dunno if this is too late to help but having just recently finished Sandhurst I can remember what we went through, I really enjoyed the lesson looking back but remember hating every second whilst doing it.
We were first made to leopard crawl for several hundred metres, through streams and mud, made to run around with rifle above head for a while and just generally beasted for a good quarter of an hour.
We were then shown a really good, angry and enthusiastic demonstration of the "en guard" and other positions and then the Sgt went mental and charged at the various dummies, ripping them apart with much swearing and shouting. We were then split into 4 groups of 5 or 6. We had to stand in a line facing each other and mark time, chanting something like "Kill Kill Kill" and were told to imagine the dummies had killed/raped our mothers/fathers and that we hated them etc etc and had to charge them one at a time.
I guess the biggest thing was that we were being filmed and anyone not taking it seriously (mainly the Cav) were forced to do it again and again infront of everyone until they got pissed off and put some effort in.
In summary we were beasted for no good reason other than to make us muddy and very pissed of, we were the shouted at and given alot of individual attention by the Sgt's whispering stuff just before we went and skewered the dummies.
I personally reckon a bit of pigs blood or something would make it more realistic and mucky.
Last time I mentioned that, I was told that Health & Safety had done for that old standard. Now, either it started with someone who couldn't be arrsed to get to the abbatoir, or it's the truth, I don't know......