You know, now that I think about it I think I have evidence for the delimiter bit: I have some code that controls these 433mhz rf AC-sockets. I do it in packet mode, with 0 byte preamble, and send the bytes that generate the reverse engineered code. That's always worked well for me.
But when Tom tested it, his sockets wouldn't respond. When he looked at the generated signal he consistently found an extra 1 transmitted in front of the sequence. In the end he just added a couple of 0's to the actual sequence to separate it in time from the control code and that worked. But it seems that this 1 might have been the delimiter.
Joe