Installation of two 16amp ovens

You should really have a new feed installed for second oven. It’s not good practice to have the two ovens on one feed. Your 32 A breaker would probably hold with both ovens in use but when designing an installation you have to allow for external influences. If cable is buried in walls for example or in contact with insulation then this can have quite an effect on its current carrying capacity and would then need to be derated. It’s also very difficult to fit two 6mm cables into the terminals of a 45 A dp switch. Not recommended. A good sparks should be able to get you a new dedicated circuit in pretty easily.

Should be alright. x 2 6mm cables shouldn't be used as supply for the ovens though. 2.5mm will suffice and these should go to a cooker outlet not the actual cooker isolation switch. It's normal to supply an oven and hob from a single cooker circuit so it will be fine to supply x 2 ovens. Anyway if your unsure or your going to adapt the wiring somehow then get an electrcian involved!