Replacing the drum on a White Knight Dryer - model no. CL 437 WV?

The 3 bolts at the back of the drum have worn away the holes and it's making a really loud banging and clanking noise when it's turning. I wondered if it was worth buying a new drum off the internet and trying to replace it myself if it's not too difficult. I've had the drum replaced before for this exact same problem a few years ago and it was expensive to get someone out to replace it. Any help appreciated, thanks.