These are useful should you wish to change your set up. You can convert either way, English to western or Western to English. Usually these retail at about £30 and can be located directly from Cashel or various worldwide stockists.
I came across this company in Australia. Natural Horse World
They stock girth converters to allow you to change the western fitting to English fittings. This can work with any bareback pad. Up until now I had only discovered Cashel. I will be adding this to the useful links.