The McCartney/Costello songs really need collecting together and releasing on a album i think , if memory serves me right their are 11 songs credited to this partnership.
And at least half a dozen of these songs are top notch ,what do you think ? ,is it worth putting an album out of this material , i think it would sell quite nicely .

DaveRam

Yeah, it does sound a really good idead DaveRam, they wrote some great
songs together like My Brave Face, That Day Is Done, Victoria & so on.
I did read some time ago that Costello hoped that Macca would put out a
nice compilation of those demo's as they had something quite special
about them!
2 genius's of music in my opinion!

There a bootleg of their collaboration. It's been uploaded in the bootlegsection some time ago.