Ayup fella.
Mine was exactly the same I hadn't got a clue about welding either!!!! My mate had done a bit so we just got the grinder out & cut all the rot out the took our time cutting & shaping everything so when it was welded it looked like a factory finish, the tunnel was the hardest as it was double skinned, & shaped all different ways but now it's all painted u would never tell. As I'm a tad fussy about things looking right.