Heya AndrewJohn,
The auction is on a NZ based auction site called "Trademe". Here is the link to the M-500t for sale.
There seems to be one reputable carver technician here in NZ. I'll be getting in touch with him today to find out if he is confident in performing the upgrade. As NZ is such a small place, I wouldn't be surprised if he hasn't had this amp on his bench before.
Are there any questions you think I should be asking the seller. He doesn't say much in the listing. I have requested more photos, but as of today, no more have been uploaded.
Loving this forum so far. You Carver owners are a friendly bunch 🍻