Okay the tubes arrived yesterday and now I've tested both of them, changing the 6080 the crackling noises went away but the background hum was still there though slightly lower. Chaning the 12AU7 tube the amp is now dead silent as far as I can tell! 
The big 6080-tube looks alot more like the Bottlehead logo so that's nice! I also think the sound is a tad better but than could just as well be placebo...
FANTASTIC NEWS!!! 2 problem tubes, who woulda thunk it, but it happens. The heaters are AC and I know there are some 12AX7's that tend to produce hum with ac heater supply (The Svetlana 12AX7 new production tubes back close to a decade ago come immediately to mind). I wonder if there are any specific 12AU7's, old or new production that are particularly susceptible to it.
Anyway, Viktor, I would highly suggest looking for some deals on ebay, or elswehere, for some tubes, atleast as spares if money is tight. Many NOS or good UOS 12AU7 and 6080 / 6AS7 types are inexpensive with very good deals to be had. The telefunken, Amperex, Mullard etc. 12AU7 types can fetch a good deal more, but there are even deals to be had there (not as much for Telefunken) if you want to try some.
For example, I recently picked up a Silvertone labeled Amperex (Herleen) that tested NOS range for 5 dollars (US). There are quite a few European based tube sellers on ebay with the more "botique" tubes so shipping cost would be less for you. But some very good steals and deals can be found from North American sellers that would offset the bit of additional shipping cost. Those tubes you dont favor you can turn around and resell if you want to.
Anyway, glad your Crack amp is up and running now.
