Hi, Welcome to Reef2Reef!
I'm not able to discern much of anything in the photos. There does seem to be some skin issues behind the eyes, but ahead of the dorsal fin, is that what you are describing? Is the fish still feeding well, is it showing any physical symptoms?
A one minute FW dip shouldn't be done, it needs to be a full five minutes, I only pull fish after three minutes if they are having a severe reaction. If it is flukes, they don't really start dropping off until around four minutes in. I'm not suggesting that you do another dip, just an observation.
I'm limited in my advice as I'm not familiar with many medications that you have in the UK. Do you know the active ingredients in the two medications you have? Would of warning - if the bottle doesn't list ingredients, you should consider not using it. Here in the US, there are a lot of "tonics" that hide their true ingredients, and many of them simply do not work.
Jay