You are correct this is most likely to be a fuse if its totally dead.
The machine doesnt have a dead switch or fail safe mode.
I know you advised you checked the mains circuit but wanted to make sure what I would do is what you have done\proven.
In most common installations you have a service\utility switch above the worktop so you can turn the mains off without having to get to the plug socket the washer is connected to, could the switch have been accidentally turned off?
Have you checked your circuit breaker encase the washer is on a separate fuse (RCBO)?
If the above look ok, the next step is to pull the washer out. I would first unplug the washing machine and plug in another (working) mains powered device to confirm power is going to the socket.
Assuming the side lamp or what ever you use work, I would then remove the fuse from the washer's plug and test with a multi-meter (or just replace with a working fuse).
If the unit is still not coming on, its likely to be a loose wire, and it now gets move involved.
Let me know if the steps above resolve the issue, and if not I will happily talk you through troubleshooting the other internal workings.
If there is a fuse it should be serviceable, ie you shouldn't need to remove any panels to replace it.
I have been looking at the different varients of your machines WI14S440.
Can you send me the E-NR number for the washing machine, its normally located on the back of the appliance, and will allow me to get the engineer manual for this product.
Good news you manged to get the E-Nr so at least you can be sure your ordering the correct replacement part.
I am still awaiting bosch-home.com to send me the siemens engineering manual for your product, ill happily send it on if they ever get round to send it to me.
The 'oil' is most likly comming from the capacitor, but it sounds like you have a good handle on what your looking at and need to do to make the repair, and I wouldnt expect you should see any other issues if the brunt of the surge was via the earth/grounding cable.
I would suggest that you install a fused spur or plug going forward, as that could have saved you a cost repair.
In order to close the case, I would appreicate if you could please rate my answer today.
Have a good evening