How to use my new oven?

I have just bought a Rosieres gas cooker, and the temperature cannot be set lower than 340F/170C. This is far too hot for many of my baking needs. In 50 years of baking, I have never seen an oven with this limited range. Is this now usual? Would you believe I have been told to bake with the oven door open?! Any hints, apart from junking the thing?