On my P reg RE Megane, it actually broke when the battery went flat. The 'electronics' light stayed on, but it was great with no annoying immobiliser. A few weeks later I think I had to fix a problem with the electric windows and somehow managed to fix the immobiliser too. I wasn't too bothered until now when my plip system has gone crazy and the only way I can get it to work is to take the fuse out and leave it out for a while.
There is an answer of sorts in there, but sorry its not a great one
Andrew Robinson, December 2007