A 'pang' and it was over

Unfortunately not in a good way. I went to pick up the blue Aerospace Sport frame which I had been given last year and which I'd planned to re-vamp for the rally, but I'm not really sure if that's going to happen.
As you can probably remember, it has a pretty mangled, stuck seat post and the plan was to cut it off, bend it back so I could insert a socket or something else strong to avoid the soft alloy tearing (more) when clamping the whole thing into a vice. I was curious if I could move it with a bit of rust dissolver sprayed beforehand and, since there were already two holes in the alloy, I stuck a screwdriver through them for leverage and pulled to one side. I heard a pang and got all excited as that's normally the sound of metals (alloy and steel in this case) parting. I tried again to find that I'd only widened the holes. Fine, I thought, it's probably better to not force it like this. But what caused that pang? I investigated the frame a bit more and found a split in the back of the seat stays: my heart sank. This operation had suddenly become major. To be fair it's nothing that I could have prevented; the tube had been through hot/cold treatment last year and there's age to be considered. 30 odd years are not to be sniffed at. The way I see it: rather now than later, when the frame's all freshly painted. I wish, though, it hadn't happened at all as it'll delay my plans. And I'm not entirely sure if it can be fixed. If not there's always Shawn with his cracked seat tube. I hope this is not developing into a pattern ...
And just for the terrible pun, I'm going to share with you some cracking pictures.

A prominent split

No band aid can help here

Cracked seat tube

Viscount Aerospace Sport cracked

I'm in touch with Steve, who will hopefully get back to me with positive news. If so, The frames will be sent off for repair and powder coating. The fork of the blue bike has its chrome intact, which means it just needs a lick of paint. I'll keep you posted on this.