Just wondering if either of these 2 would work, I assume you start at the lowest setting and work up?

As I think a new order S7 has one blade effected.

http://www.amazon.co.uk/TRIMMER-TURN-50K-3006P-1-503LF-BOURNS/dp/B01186ESAM/ref=sr_1_1?s=industrial&ie=UTF8&qid=1460404535&sr=8-1&keywords=Bourns+3006P-1-503LF+50k

http://www.rapidonline.com/electronic-components/bourns-3006p-1-503lf-50k-3006p-10-0-75-multiturn-cermet-pot-68-0140