I was introduced to AO quite a few years ago, when our washing machine went pop. The engineer recommended them. I was on their website at just after 5pm, new washing machine arrived just after 7am next day.Didn't know about AO - I'll look into it - thanks.
Used them quite a few times since for other stuff. Longer delivery times are cheaper, or free.
Oven should be just three fat wires. If you can get at them behind the unit. Oven probably just held in by those four tiny screws you can see with the door open.
It is at eye level. Place your Workmate table (or something similar) in front, slide it out onto it then disconnect. As long as you can handle the weight. But you have a boy can help with that.