Thanks for the good words folks.
I'm a bit calmer today and ready to take on this problem at hand.
I'll try to get some picks of the obvious signs but obviously the rubbing is something you'll have to take my word on. My biggest annoyance is my own confusion on this whole thing. I really can't figure why water changes seem to bring the flicking and rubbing back on. The flicking eventually stops to a point of it rarely if ever happens, yet the fin quivering is still there
I've tried doing water changes at the same time each day to rule out a suggestion of ph changes during different times of the day but it makes no difference.
When I did a water change yesterday, one of my smaller tapajo's went nuts for about 10 minutes darting around like mad and rubbing like there was no tomorrow. This happens every water change now with the majority involved.
My main concern though is the sevs issue. I can only describe it as having the look of a long blood blister in the gap between it's gills under it's chin. It looks to have something tiny dangling from it but I don't know wether to put it down to damage from rubbing on the bogwood or something else.
On the other hand today - They are all still eating like pigs, pooing normally and the sev seems to be the only lethargic one.
The large tapajo has spent most of last night and today digging 2 large pits under the bits of bogwood. Been quite funny to watch as it scoops it out bit by bit with it's mouth and dumping it all into a huge mound at the front.
The big tapajo does have some large whitei'sh spots on it's fins though, which it had when it arrived. It looked like it had been quite beaten up when it arrived so I didn't know what to think about that.