Diego,
As Lon pointed to, it seems many CV4080 are also listed as 75C1. I have a nice collection of OC2 and O_2 variants, different makes and voltages. Though I like them all for different reasons, 75C1s stay in my Toriis, though I have not got any CV4080s. My 75C1s are labelled differently, but look very close, glass and construction-wise, some Valvo, some Phillips, some English Valve Company. I think I have some RFTs around too, maybe called STR75.
I have seen Amperex and Phillips labelled 75C1 that also say made in England, and some without "made in England."
The tube data I found at
https://www.radiomuseum.org/tubes/tube_cv4080.html showed 75C1 as "similar," the voltage slightly different, the CV4080 @78v and 75C1, 75v. Both have a range from 2-60mA...so very close, if not variations of same.
M8225 appear to have identical specs to CV4080, 78v/2-60mA.
OC2s have the same voltage spec as 75C1 with a different amperage range, 75v/5-30mA...
I bet the CV4080s will be nice tubes. If you get a chance, let us know what you think of them compared to the stock tubes that came with your amp.