Door bell timer using 555 IC?

[Yorkie]

Well I have to say that I'm overwhelmed and really very grateful for all the interest, advice and trouble that everyone has gone to, for what - for me - had started out as a simple 555 timer!

I'm indebted to Nick for the time he's taken to outline possible problems if a called hangs onto the push button, and for the suggested mods and simulation.

I've developed the PCB to a point at which there's just no more space for additional components, so I'm going to give it a go and see what happens.

Serves me right for not persevering with two transistors, 4 resistors and a cap!

I'll report back in due course after other diversions over the next few days - weekend away for NVCF, Sheffield Monday,  Stately Home visit Tuesday, friends visiting Weds,  and so on it goes...