At the interview for my current job, the panel said they were going to let everyone know on the friday. The interview took place on a wednesday afternoon. They were interviewing weds & thurs. I had an interview that friday, one of those horrible all day things. I was out of work, so had applied for loads of stuff. The head of the panel stated this and asked if t was ok. I hesitated for the tiniest moment, and they picked up on it, the head of the panel saying "obviously it is..."
I explained the interview friday, and that I wouldn't be contactable. I left feeling I may have fucked up.
The head of the panel called me at 4 on the thursday to offer me the job. Apparently they knew in the interview they wanted me for the role.
I do feel sorry for the poor souls who went through the thursday interviews for little purpose. I now work with most of them...
You've little to lose by telling them, and it only becomes a bigger thing the longer you leave it. Plus, if they really want you, it's a signal to them.
Very best of luck to you, whatever you decide mate!