It is often said music has a healing power. And nowhere was that more in need than as the sun set over a large crowd in Margate last night. Because many of those filing into Dreamland to pick their spot before the venue’s Scenic Stage amphitheatre had just witnessed a thoroughly miserable display by England which did much to dispel the theory this team could actually win the Euros. Not, it should be said, that those providing that necessary tonic probably gave two hoots. Because both acts hitting the stage on Thursday night as part of the Margate Summer Series of big-name shows were proud Scot…