Don at Bintel is great for cleaning optics I have had two 8" SCTs cleaned by him without issue. He has been trained by the manufacturers of these scopes. I am sure if you email him some photos he will advise you one best way to proceed.
Alternatively ther is a Rogers optics in Padstow you can try, but as yet I have not used him. But have got some good advise from him.
http://www.rogersopticsrestoration.com.au/index.html