Where else could the fuel pump be other than under the back seat?
I left my Ford Fiesta parked up 3 weeks tried starting it and it what fire up you can't smell any petrol when trying to turn it over so i lifted my back seat and there's a small black rubber with a black caged wire leading out of the body work But the petrol pumps I have seen on video and online seem to be a lot bigger than the one I'm looking at is this the petrol pump what I'm looking at one other thing my fuse box in the engine bay the black cover doesn't give details of what fuses are what what amp is my relay fuse and where could it be in that unit 
The fuel pump is mounted on top and inside the fuel tank. You have found It as it is located under the back seat under the rubber cover. Remove the black rubber cover and there's the fuel pump. The fuel pump fuse is F11 which is a 30 amp fuse located inside the fuse box under the hood. Look on the underside of the fuse box cover for the location of fuse F11. The fuel pump relay is located behind the glove box. I think the relay is R6 but not 100% sure. There should be a decal showing which relay is for the fuel pump. My be on the glove box.
For many several years now, the petrol pump is placed directly into the gas tank!
Blame the fuses first and swap them around to see if just by removing and installing the fuse that may have made a connection on an otherwise corroded connection.
3 weeks is not a long span of time. 3 years is not a long span of time either. THAT should not be your problem.
All fuses in fuse box are clearly marked out to where they go to. FP is one of them.(I don't believe it is called a PP)
Fuel pumps in MOST modern cars are actually installed INSIDE the fuel tank! Sometimes, there's an access panel built into the bottom of the trunk (boot), but other times, the fuel tank has to be removed from the car to replace the fuel pump.
If you're looking for fuses, READ the owner's manual that came with the car. It should have a listing or a diagram of all the fuses.
Do a search on youtube for replacing the fuel pump on your vehicle.
Before you really mess the car up, get it to a mechanic. At least look at a few youtubes to get an idea what you're looking at. Try looking at each fuse so you can find a burned out one to replace. They have numbers on them for you to match a replacement.
The fuel pump is RARELY, if ever under the seat. It is NORMALLY in the fuel tank. Some older vehicles had it near the engine. In any case, if you trace the fuel line from the engine back the the tank, it will either be there, or in the tank.
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