I contacted Surly, they are understandably busy due to the coronavirus and said it's about 4 days for a response.
CliffordK: I'd rather not post my location. I'm in a medium size city. Sorry but an endoscope is one gadget I do not own. I took the cranks off to look inside, but could not see inside seat tube on the other side of the crack. Your point about the welder doing a poor job on other joints is what I'm concerned about too. I'll see what Surly says, maybe this is an (internally) known issue. Thanks for your thoughts on this.
I would prefer to use a welding shop rather than a frame builder due to the cheaper cost and easier accessibility. I'm one of those living car free people.
Due to the coronavirus I don't see myself renting/having access to a car anytime soon, so the shop would have to be relatively near by. There seem to be many shops in the area but I'm having a hard time finding one that seems suitable, i.e. TIG precision welder. Do I call places until I find one that does freehand TIG welding? It seems all the places that explicitly say TIG welder are all driving distance.
Luckily I'm not in a rush to get this fixed as I've had more occasion to ride my 1x1.
Thanks everyone for your insights.
canopus: great story.