Originally Posted by
Sixty Fiver
...On most days my left leg is a little numb and lacks some reflexes it should have...
Have you thought of trying powercranks? A few people have used them to correct their leg imbalance due to nerve damage. It's not a 100% cure, i.e., you may always have a slight difference, but at least your legs will be doing the same amount of work rather than having a resting/trailing leg.
The guy that invented them, while he can controversial, is a retired MD so I'd suggest e-mailing him and trying to find a demo.
http://www.powercranks.com/v4pages/videos-list.htm
http://www.powercranks.com/v4pages/support-contact.htm