Ok as for the main oven the seal you can still get. They are pretty easy to fit as it just clips in to each corner and stretch over so that's not hard.
Click here for the main oven seal
But for the top oven the seal is obsolete so that cannot be brought sorry.
As to the hob that model number isn't coming up. But from the sounds of it the switch is proberly faulty. But without details this will be hard to get.
But as to the dishwasher the E25 is a draining error code.
If all the drains are fine then you need to scoop out all the water inside and then remove the filters in the bottom.
There you will see a cover. You need to prise this up and in there you will see the pump impeller. Just check theres nothing blocked up in there. If you have the manual for this it will show you how to remove the cover.
Once its all clear refit the cover and retry it again. But if still the same then is possibley a faulty pump which will need to be stripped down and replaced.
If you don't want to do that part let me know were abouts you are and I can try and find a local engineer for you.
And yes im in the UK aswell.