I don't think it's going to be any less dodgy than using a 3rd party battery and at least with the charge it won't go anything to your camera. The worst that could happen will be that it cooks one of your batteries.
I had a 3rd party charger for my old bridge camera and that was fine.
Can you not find a Sony charger on ebay?
If you do buy it, charge your 3rd party battery in it first, so that you don't ruin your original Sony battery.