Brandt/De Dietrich do charge for instruction manuals and, from memory, they are about £6-£10 a throw. No downloadable version available for that model, I checked.
Your cutting out problem is likely to be either the main oven stat faulty allowing the machine to cut out on the safety stat or the safety stat itself faulty. The instruction book won’t help you there so there’s no point paying for one. 😉
If the timer were faulty you’d get different symptoms on that machine.
Hope that helps.
K.