I want a sturdy, loud, shiny and proper bell. Mechanical, no plastic, chrome would be great. Any bike shops selling such?

Aye. The Bike Chain in Edinburgh

http://www.thebikechain.co.uk/PUSH-Ding-Dong-Bell-2010043001/

A proper ‘Bing-Bong!!!’??

They are available in many shops in London.

Happen to have one of these next to me right now, that exact one, still on the display card if you were after it as a pressy. They do do chrome ones as well though.
edit-not as big as that big one up there though!

freshtripe have some lovely ones in brass and chrome.

Have large chrome belss with a proper Ding Dong in stock at Rik’s Bike Shed at Drumlanrig!

I have a large Swiss cowbell. Ideal as it rings constantly as you ride informing ALL wild life that you are about to be passing at an unnatural speed.

HTH

the cowbell would slow me down due to its aerodynamics. It needs to be a proper DING-DONG bell.

what you need is a carbon fibre XTR RACING bell

I had a lovely large ding-dong bell on my commuter. However when off road it rings everytime I roll over a pebble, so not much use unless you want to wear earplugs while riding.

It needs to be a proper DING-DONG bell.

That’s what druidh posted. 8cm diameter too.

How about this?
” a disc of stainless steel with a little spring pinger.”

http://www.kinetics.org.uk/html/bells.shtml

SC, yuk!
Druidh’s suggestion is being looked into. Need to contact them to see if they will post to the bastard child of Great Britain Ireland.