Simon, go the www.niceproducts.com.au
They make them standard sizes and longer as well. Repco are distributors so when you pick what part number off the web, repco (& other car parts stores) can order them 4 u. They don't sell direct from memory.
I bought mine off the shelf... find the matching stud number and add two zero's for the correct part number ie NS340 are standard length, NS3400 are the longer versions.