Parts for; Dyson DC18 Pedal Plunger 911099-01

I'm after a part named a "Pedal Plunger" for a Dyson DC18 vacuum cleaner and I don't care if it is non-genuine.

Can you please confirm -

1. do you know if or where I can get this part ?
2. what the part would cost ?

According to various Dyson parts catalogue the part number for the DC18 pedal plunger is:  DY-91109901 and it is a clear T-shaped item.