'Changes', a cover of the Black Sabbath original, is now 16/1 for the festive top spot, a significant shift from the odds of 50/1 quoted before Ozzy's accident. A spokesman said: "The pair have been backed down to fourth favourites and if they have as much support with people buying the record it is a real contender."
Doctors have said that it may take up to two months for Ozzy to recover from the injuries sustained, which included eight broken ribs.
The Pop Idol finalists' version of 'Happy Xmas (War Is Over)' is still favourite amongst bookmakers to top the chart come December 25th.