FINAL UPDATE: The buzzing was stopped by moving the mains cable over to the side underneath the machine. It was interacting with one of the components but I don't know which one. The proximity of the bluetooth receiver to the transformer did not appear to be an issue.
So, here it is my Philips 462A in all its glory. Playing clear and loud and looking absolutely fantastic!! I love it and my friend saw it today and was knocked out by it and now wants one herself! Thanks for all the help, especially Lawrence of course. I have learnt so much on this journey and am dying to start on my next radio set (I have already got one in my sights but hopefully it will be a little more straight forward next time!).
The set plays digital music now rather than its original AM frequencies so its not a 100% restoration but it will now get used again rather than sitting covered in dust in someones attic. I decided to remove the AM frequency receiving components in the end so they can be used in a restoration by someone else (on sale in the offered section here if anyone's interested).
Thanks again...until the next time....
Nicola