How to "un-strangle" a seat tube?

[danson67]

If only Paul Brodie was my neighbour...

If you feel like trying yourself, the tube blocks are available locally from this French manufacturer, €30 each:
https://mt-frameparts.com/en/tube-block/77-137-tube-blocks.html#/51-bore-286mm_1_1_8


All the best,

 

[foxb13]

Really nice find @danson67, many thanks.