Edward VIII Artillery Officer's Sword

[Royal]

We have recieved a rather tatty gunner officer's (I think) sword with an Edward VIII monogram on it through the family.

This makes rough sense as my wife's grandfather was a (territorial) gunner officer throughout the late unpleasantness. I know his service number and have found the Gazette enties for his MC, MiD and post-war retirement but cannot find when he was commissioned. We have his medals, miniatures and SD jacket so this is an addded bonus but I'm wondering whether to get it cleaned up (and if so how and by who) and/or insured?

Any suggestions?