Thanks for that Mig. I'm trying to contact YorkOptical in Brisvegas atm but they don't seem to want to answer their phones
I had another good look on Saturday and there is definately fungus down the insides of the OTA and on the mirror. Looks like a full pull apart and clean.
I've has a positive response from the Observatory Committee that it needs to be done they realise that this is part of ongoing maintenance costs of a scope in the humid subtropics so if I can find a company that will do the job at a reasonable cost that will be our preferred way.
If I can't find a company to do it (and I'm sure YO will if they can answer their phones) then it will have to be an inhouse job. As I don't have access to a UV light it looks like the Ammonia/peroxide option may be the way to go. I'm still going to try to contact YO, as I'd much rather they or someone similar do it than me. Maybe Roger D will see this thread and offer his feelings? I'm sure he's had to do it a time or two.