If a part is temporarily unavailable, you could substitute it with these parts:
Quality Fuel pressure regulator for Volkswagen GOLF 2.0 BiFuel 116 hp Petrol/Compressed Natural Gas (CNG)
Wide selection of new fuel pressure regulator for VW Golf Mk4 2.0 BiFuel Petrol/Compressed Natural Gas (CNG) 116 hp, priced from £8.48 to £56.72. Choose from 5 trusted manufacturers.
Tried, tested, and top-rated: Fuel pressure regulator for Volkswagen Golf 4 (1J1) 2.0 BiFuel 116 hp Petrol/Compressed Natural Gas (CNG)