Geege,
Depends on the individual Force as to whether they allow Officers to take up alternative paid employment whilst on a career break. Generally, if it is purely to 'sustain' yourself whilst on time off then it doesnt appear to be too much of an issue.
I took a 12 month career break 3 or 4 years ago to pursue my ATPL's etc. Now happily flying with UK airline....no regrets whatsoever on leaving my previous career.