Rob,
Thank you for your response. Apart for the continued US Centric couple of replies from Ring, which have proved almost useless, I have received no help I’m afraid. I have purchased one of the Ring.com Forum site suggested Resistors from the US Digi-Key Company at a total cost including carriage of £21. Even having fitted this, it still has made no difference. Th size incidentally is almost exactly as you describe. I mounted it on a small piece of wood. I am a little perplexed by your suggestion of your Transistor. The model you describe, and shown on the B & Q site, is for fitting to a Rail on a Mains Distribution Board. Is this how you have fitted yours? I am looking to fit my wiring for the mains to my Bell Push from a Spur off an existing mains circuit. Can you tell me how you identified the circuit on the DB for the Bell Push. I suspect there must have been a pre-existing Bell Push and chime some time in the past.