Does anyone know where one could find a left hand OP Rod adaptor for a K31 Swiss 7.5x55?

That's akin to looking for a needle in a haystack.
Just guessing. Try Numerich arms or Gun parts and see if they can help you or direct you.
You might have to find a quality gunsmith or machine shop and have them fabricate one. Offcourse you have to find a blueprint or someone to lend you the part.
Lastly see if there is a Swiss K31 forum on the net where you can be assisted.
Best of luck to you.

The K31 forum would be the best place to ask. That said, I have seen them for sale on ebay back in the day when I was looking. From what I remember when I was looking the factory-made stuff was quite rare, at least stateside, so I'm not sure what they sell for.

With stuff like that I'm used to the habit of waiting until something pops up, but the Swiss forum might be a quicker fix.

http://theswissriflesdotcommessageboard.yuku.com/
Check with people here!!

I have two rifles with Lh bolt adapters. I bought one rifle with the adapter already on it. I bought the other one from a Swiss or Austrian. I'll start looking for my contact.

I contacted the source from whom I purchased the LH operating rod. The gentleman has died but his wife can sell the parts. Here is the response:

I can still help you with a LHO
The cost is $ 260,- for the LHO and $ 25,95 for insured sending. Please let me know if you are interested in my email address:
mjclammers@hotmail.com

Please contact her directly if you want one.

Allan

Just in case someone doesn't know what the discussion is about, here is a picture.

Mr. Smith got the last one she had, but she probably can get more. That price is a lot less than I paid for mine because of the reduced value of the Euro. If you ever thought you'll need one, now is the time to buy.

Good luck.

Can you show what a rifle looks like with it on?