now the question I have is can you have a wood burner without a chimney – ie can the flu go up the wall and out the wall at an angle?
Yes but only 2 No. 45 degree angles allowed, and it will actually be the stainless steel double skin bit if the flue that needs to penetrate the wall, as per the very top of the picture above. To conceal the ugly transition (IMO) We constructed a “fake” chimney breast, as our lounge was just a square box, so all the flue bends and wall penetration are hidden being a fake plasterboard chimney. You wouldn’t know any different unless you went upstairs and saw the chimney didn’t continue up through the house.