The tall oven has stopped heating up even though the fan and light still work, any idea, are there fuses fitted within the cooker?

Probably the element has failed. If it is a fan oven, the element is around the fan at the back of the oven. You take the covering plate off, and then remove the element usually attached with a couple of screws. Turn power off first!
Check continuity of element with a voltmeter. If it has failed, they are usually available on-line