Well the main boiler looks well made and silver soldered, and is of the mammon style, the steam valve is a later addition (replacing what would have been there), yuk hate the 2 BA cheese head (look at mamod boilers and you will get the idea)
And (sorry)looking at the end of the boiler where the stay comes through, although the boiler should not need a stays as its PSI will be about 25-30 (tops) so to be honest it is a well engineered boiler...............however (as always) it looks to me as if the stay has leaked and been blobbed with soft solder !!
It should be under the 3 bar rule, but personally I would have a test, just for your own benefit
Hope some of this helps
