did you try wiring in series on 16V?Update on the additional Door Bell Chime saga!
I swapped my 8v/1A Transformer for a multi Volt Transformer from Screwfix. If it put it on 12v or 16v the 1st Bell Chime ding dongs lovely, and there is even a low volume 'Ding' from the 2nd Bell Chime, but no 'Dong'. A step forward but not perfect.
If you press the Door Bell multiple times it will make the 2nd Bell Chime 'Ding Dong' a little.
So with the multi volt Transformer, the higher the voltage, the lower the amps (12v is at 0.7 amps), so is this a case of needing a 8v/2A Transformer, as suggested by Flameport earlier? That would also fix my illuminated bulb problem right?