I have just been reading through the ellisons catalogue for you too try and get some info for you and i THINK that yes you do have to purchase the heater for the best results. Im not too sure about whether you need one for the facial masks though??
In the catalogue they also do an intro kit have you seen that?
It contains the heater, 21 blocks of swiss chocobeauty, orange massage cream, 3 face masks and a dvd. For £240.
I think you need to give ellisons a ring and have a chat about what you need just too be sure. Also as its alot of money it might be a good idea to advertise the treatment before you purchase anything, to see what response you get.
Hope this helps a bit hunny x:|