BSA A65 Barrel leak from tappet block

[Rocker mark]

thanks i will contact them, as I said I am that man in a shed, I do oxy acetylene braising and MMA welding in my shop, neither are suitable for this as there's no room to drill the ends of the cracks to prevent them spreading further, the rusty barrel replacement cost £130.00, so maybe I can get them to re sleeve this replacement barrel due to the previous job failing.

although I won't hold my breath as their work is not at fault here, the crack is not in relation to the bores themselves.

[Rocker mark]

for clarity on this, originally I had the bores re-sleeved thinking the leak was caused by a crack in the bore, after the re-sleeve the problem was still there, my concern is the crack continuing because there is no room to drill each side of a crack in the area of the leak, so I have bought a second set of barrels which are in a sorry stat but are standard bore, the plan as of now since some useful posts here, is to contact the people who re sleeved the last barrel and have them either rebore or re sleeve them, depending on costs, the reason I am debating this is a rebore would not weaken the barrel, as barrels bolted via a skirt rather than studded straight through barrel and head are inherently weaker, so that's sort of where I am on this at the moment, I would rather not buy more pistons, but If I have to I suppose I will, I would have been happier if the engine center had checked for cracks before carrying out the work as I did report to them exactly what was happening, I shall have a word with them.

thank you all for being so helpful.

here's the lovely and 100% original 1962 A65 just for fun