"McGrath said, a bit of a bugger (though I think that may be harsher language over where he is than here)

No, that's a pretty mild expression in my part of the world. My eminently respectable piller-of-the-church 89 year-old father-in-law would say it without turning a hair, to refer to any minor problem, and so forth.

In this context all it means is, it would be a little difficult to sing those words to that particular tune.