New member asking for help with 6056 please

[Rothstein1928]

Hello all....

After 20 years of ownership I've decided to find out a little more about my watch !

I'm told it's a 1948 5056 / 6056 ?

My main question is about the crown, should it not have the logo on it ?
And what specific true of crown fits ?, there are many in eBay but I need to know the specific one I require ??

And who would you recommend to fit this and service the watch in Nottinghamshire are ?

The dial says chronometer, yet the internals don't ?, is this typical of the period ?

Lastly, does the front pull off ?, and should I clean the dial ???

Thanks in advance to anyone who can advise

Stuart