Hello Kev,
I just want to warn you about this offer !
You are asking someone you don't know to refine +700$ worth of gold.
Pick the someone carefully.
Also, think about it... 40$ for the refiner who will do the job, I don't think there are benefits to take such an offer. You must consider the chemicals cost + the time taken to refine this gold which is AT LEAST 5 hours. (Maybe Harold was faster lol) At the end, he does not get much for the time he worked...
Well this is just my two cents but be safe.