Go for it.
The legality is questionable, but a cover version ranks way down on the lawyers' list of priorities (as long as P2P file sharing is alive and well). The worst that would happen is a "cease and desist" email arrives in your inbox, and if you generate enough attention to garner that, you're one lucky band.
Bands play covers all the time in the clubs, and the club might even pay "protection" to BMI or ASCAP for a blanket license over the whole establishment.
There's a whole subculture of mash-ups that use the actual copyrighted recordings, and the recording industry has actually warmed up to them and even officially releases the good ones.
In short, if you're not costing them money, they don't care. You have my personal Gnu Odor guarantee that nothing bad will happen to you. Upload that sucker, 'cause I want to hear it.
Addendum: all that said, I can't guarantee MySpace won't kick you off if you post it there. If you don't have webspace, send it to me and I'll post it.
P.S. I had to look up "chav," and I'm really sorry we've apparently exported that "lifestyle" to the UK.