I would wall mount the TV above where the hi-fi is now and position the speakers either side of the fireplace, ideally with some space between the cabinet edges and the fireplace itself. This would help to make the best of the speakers you have whilst also opening up the possibilities with anything new.
Bingo, why didn't I think of that .... may well be the best answer ... certainly the speaker on the right can move to the right quite a bit and I can pull them quite forward so they're hardly in line with the chimney at all.
Other advantage anyone sitting in the armchair on the left could also see the TV.
I was thinking about this and whilst I agree the best room acoustics will get the best out of any system ... surely if you take a speaker that's "bright", it doesn't matter where you put it ... it'll still be bright in comparison to others.
Tonally my AE Evos 3's were lovely (in the same place) but there wasn't anywhere near the same level of detail.
Anyway ... just a bye the bye comment as I sit here lstening to an Amazon Playlist .. Acoustic hits and completely blown away by the sound