Can i run a single oven and seperate microwave on the same supply?

Regulation 314.3 states that the number of points supplied by a final circuit, shall be such as to facilate compliance with the requirements of chapter 43 for overcurrent protection, Section 537 for isolation and switching and chapter 52 as regards to current carrying capacities of conductors. The 6mm twin and earth cable is capable of carrying 40A or 9.2kw . Even with enviromental factors this is more than enough for your oven and microwave. Section 537 simply states that a means of isolation should be provided for mechanical maintenance which you have. Chapter 43 Will also have been met so long as the Zs reading of the circuit is lower than the maximum permitted by a 32A mcb. A 60898 Type B breaker has a max Zs value of 1.15 . for a 6mm cable to fail this it would need to be over 100 meters or have a fault. So long as your circuit checks out there is no reason why you can't have multiple appliances running from a single isolator. Just make sure the isolator can handle 40A and you run 6mm cable from isolator to outlet and a suitable cable from outlet to the appliance.

Yes what your proposing is fine. It would be best to retain the 40amp isolator switch and feed two 13amp unswitched fused connection units, one for the oven and the other for the microwave. Remember to apply to your local authority for consent to carry out your own DIY electrical work. As all electrical work in the kitchen (even minor alterations like this) come under part p of the building regulations. So carrying out work without having paid the appropriate fee and obtaining consent could make you liable for a fine of up to £5000. The local authority will also need to inspect and test the work you do once its completed. As its a simple job, you will probably find its more cost effective and quicker to hire a part P registered electrician to do the job, as they can legally self certify the work that they carry out. Google part P for more information if your unsure on the law.

any electrical works in a ktchen is notifiable so if you are not part P registered then leave it to someone that is, regards Terry.