Trip switches I am afraid, they can be a pain in the bum.
If it is tripping with both the heater and extraction system on, turn the heater off, if you have them both plugged in to the same socket, change the sockets around to that they are on different ring mains, ie plug them into two different locations, one in the living room and one in the hall way.
If it is tripping with just the motors running and not the heater, turn on one motor and leave if for 20 secs to get up to speed then turn the other motor on, if all of this doesnt work, you just cant do the work, its no point in putting a miniature circuit breaker "MCB" on the end of the plug as they just don't work.
Hope this helps
Aidan