On 6/11/2015, Mark Hester wrote:
"Hard to get wiper parts are available from this place
who sells extensively on eBay at reasonable prices.

Here's and example with his email address:
While it may last, eBay item number 271899803024
email: steve@stevehunt.demon.co.uk

"I recondition Lucas wiper motors for classic cars and sell wiper parts". -- Steve Hunt