I have now used Ubuntu for about two years; side by side to Windows on the same hard drive. As I am getting a little bit 'fed up' with U I'm thinking of installing a different Linux distro (eg Mint) but obviously keeping Windows and, preferably, my Linux home folder intact.
Is this fairly 'do-able'? Or will I be better off backing up my home folder and copy it back when the new distro is in place?
And what are the risks to my Windows partition? My Linux partitions are only two at the moment; a swap partition and the main.

Regards
ollie

Ubuntu derivatives will (usually) respect your Windoze partitions. I've done dozens with-out issue - note my sigline however.
You do not want to use the same /home - you *especially* do not want to restore it after a new build. By all means copy up files/folders you require, but not the whole /home.

If you still like Ubuntu but don't like Unity just switch to Gnome classic at login session selection screen or install some other Desktop Environment(hope you know how to do it by now?). This would be much better solution. However if you prefer something else over Ubuntu just do backup and install as fresh. As suggested before - don't copy entire /home folder just files and folders you need transfer.