The most reasonably priced component used on the Lt80 1992 (n) General United Kingdom (e01 E02) Fuel Tank is the Washer,lock.
The Fuel Tank assembly is constructed from several parts from which the Tank,fuel(blue) is the most expensive.
With a quantity of four pieces, the Washer (8.5x29x1.6) is the most used part in the FUEL TANK diagram.