Absolutly gutted. This project was never finished to how i wanted it due to constant budget constraits, so many things i wanted for it, but I used it nevertheless. I put that crack to the back of my mind and continued using it as it such a fun bike to ride, until today I decided to have another look. The crack has got longer and the worst bit, there is a hairline crack in the downtube section now as well.
So i've stripped it down this afternoon awaiting a day when i have a bit more of a budget
Here it is getting worse. I used touch up paint after chipping it before and it's clearly a crack behind the weld. This would be caused by local case hardening due to the heat of the original welding and it's exactly where you would expect a crack to be.
Second picture showing the new crack on the underside of the downtube.