I recently replaced my leaky fuel shutoff valve using the same style valve shown from a different ebay store (latch type with 45 degree angle) and it is working well at this time.
With the loader attached, the tank empty and the engine cool, I was able to reach in with a box wrench and loosen the fuel line nut and then remove the two bolts holding the valve to the tank.
I did find that the provided o-ring was slightly over-sized and the screen was slightly under-
sized. I cleaned and re-used the original screen but was able to squeeze (roll) the provided o-ring into the groove of the valve.