Nice one. I thought I read appendix b for that rule, but apparently not well enough!Rule 26-712(a) - Appendix B
In laying out the location of receptacle outlets in residential premises, consideration should be given to the placement of electric baseboard heaters, hot air registers, and hot water or steam registers to avoid having cords pass over hot or conductive surfaces wherever possible.
It's a "should" not a "shall not" though.....
also if you read the instructions for the heater it will most likely say the not to place it under receptacles, I know Dimplex does.