wanted: petrol tank gauge sender - rubber part- (doesnt have to work)

am wanting to block off one of the openings on an 1100 fuel tank, am after the rubber cap on top of tank which has a hoseclip fastening it . ..either a gauge 'sender' or the' fuel uptake' with two pipes cap will work. ( my current one one has developed a split and can smell fuel tho not actually leaking)

I don't have one but you can get a rubber planking cap from para rubber.