I have been left a large sum of Rand and would like somewhere to keep it until I have chance to take it back with me.

Is there anywhere that offers security boxes, preferably short term, in Kunming?

If so is anyone on here using them and can give me any details?

Krugerrand?

For deposit boxes you'd be looking at The Industrial Bank and The Bank of China.

The only branch of the Industrial bank with Security deposit boxes is near Yuantong temple. There you'll need your passport and visa to sign up. You will use a fingerprint machine everytime you enter and you'll be allowed 12 entries a year, any more than 12 and you'll be charged a small amount.

Prices are annual and start at 230rmb for the smallest box which can hold up to 1 million in Chinese banknotes. They have a 600RMB key fee.
Entries can be made Mon to Friday during banking hours.

The other option is The Bank of China across from JiaoSanQiao underground station. Here annual prices are 400RMB to 800RMB depending on the size of the box. They charge a 400RMB key fee and will rent you their smallest box for 40RMB a month. Entries will require your passport.

Apart from the main two there are a few smaller options but you're best sticking with the big names for things like this.

I use the Bank of China, it doesn't require a BOC account and you can make unlimited entries during their banking hours (Mon to Fri) which are a little longer than The Industrial Bank. I have used The Industrial Bank in the past (in another city) and had no issues, went with BOC due to location this time.