Hello Simon,
Hope I will get to you with this message.
I am french and I just bought a pair of SPENDOR SP100 (second hand from 1998).
I have a problem : a lack of low frequency apparently due to hard woofer surround. The speakers have not been used for the past 2 years. I was trying to find replacement surround and experienced exactly the same problem you had with SPENDOR after sales service.
I saw your post with brake fluid. I am just a bit curious before attempting this operation. I can see that you did this operation in 2012. Do you still have your SP100 ? Are the surround affected or damaged by the brake fluid ? Is it still ok after a long period of time ?
Thanks for your advice.
Best regards
Hubert