I am familiar with T. guinasana, and this species does not look like the ones I have seen. It doesn't seem to rsemble the Barombi tilapiines listed in the recent Annual Report either.
Don't have Chester's Annual Report, but this is a fairly typical Pungu maclareni, which is one of the Barombi Mbo cichlids ("tilapiine sensu lato", but work by Dunz et al. suggests that they're better placed in Oreochromini). Interesting lake system and fish, and a nice photo.
I think that's it; thank you condor. I'm not qualified to enter into questions of cichlid relationships - I guess that rather more than half of what I've read is now thought to be wrong (not hard, as so much is contradictory).
I hope there's a label on the tank next time I visit
There is now a label on the aquarium. This species is apparently Sarotherodon lohbergeri another of the Barombi Mbo cichlids. I am changing the title again