I don't have any specific info on this model. Sorry.

With a movement # I can give you an approximate date.

UK market, 9k DTE contract case, movement made around 1955, so it was cased later, which is not uncommon.

Value for this sort of thing is low, not a whole lot more than the gold.

There is a movement catalog put out by JLC which comes up on eBay from time to time.

Many of the common calibers are show in my book as well.

What metal and dial color?

Jaeger-LeCoultre, mid to late 1940s, it doesn't have a model name, made for the european market. Movement is one of the 4xx family, either 449, 463 or 469. Dial looks already redone so no harm in redoing it better. Value probably around $375.

It can't be cleaned, it would need to be refinished. It seems far gone, so a refinish would not be value detrimental.

Either should work, I think you'll barely notice a 16/14 taper.

The rotors are interchangeable, so yes, sounds like a Franken. 817 should be porthole.

Approx. 1940-41.

It;'s referred to as a "triple date", they were made from 1943 to 1949.