Nice work!
How did you patch that nasty hole in the tank?
I cut out the area where the rust had gone all the way through, this actually only ended up being quite a small area, maybe 40 x 20mm. I then cut an oversized steel patch placed inside the tank, held with magnets and had it welded shut. The rest was only very thin surface rust and the inside was in really good condition so didn't even require any kind of tank lining.
In the UK these tanks are fairly hard to come by and when they do come up they are often in an awful condition inside.