I've always wondered how a Macca/Neil collaboration would go but some of the previous assessments are correct about Paul not taking criticism well. There's a great podcast featuring Beatles biographer Mark Lewisohn I listened to where he tells a first hand story. Paul's then manager told him Macca had gone ballistic over Elvis Costello giving him an honest appraisal of his songs. The podcast is long but well worth a listen if you're interested in Macca. I can't remember which point in the podcast he tells that story. https://soundcloud.com/fabcast-870039074/013-lewisohn
Thanks, Kerouac. that was a great listen. There's a bit of CH in this particular episode with Mark Lewisohn as well.