Thankyou and farewell
After a recent leaky sunroof issue which couldn't be sorted (and which had the bonus of a foot-cooling water pool in the driver's footwell), as well as engine management failure messages, five different rattles and squeaks from different parts of the dashboard, and a hundred and one problems, I have sold my fatally flawed 156.
I've bought a 2001 Passat Turbo, and it's really amazing - handling not quite on par with the 156 but mighty close, and there's not a squeak or rattle to be heard!
Thanks to everyone who provided great advice, especially David C who is simply awesome in the time he gives to people needing help with their Alfas.
All the best with your cars, drive safely.