I have just started treatment for fin rot with waterlife myxazin and have bought a neat little gadget called amonia alert by seachem so I can keep a constant tab on ammonia levels and it is currently reading <0.02 ppm (safe).
I will give you the final report in 5 days to see if the fin rot has healed or if ammonia levels change.
Thanks again fishlady, you've pretty much helped me through the whole process of this new exciting hobby :)