Basic GCode Help (Pause on a Dremel 3D45)

I have a Dremel 3D45 and i have been seaching for a way to have a pause at a certain layer to allow for a filament change.

I have eventually discovered that if i manually edit the GCode file and add a "G5" above the beginning of the desired 'next layer' comment it works.

(G5 appears to be pause command in Dremels flavour according to here)

My issue now is that the bed begins to cool on a pause so by the time i come to change the filament the bed adhesion has gone and the half printed model has moved slightly and thus now continues as a spiderweb mess.

So i am looking to add in a bed heat up command (M140 / M190)
If i add it after the pause it obviosuly only then works on resume after filament chage (no good).
If i add it before the pause, its gets wiped out as soon as the pause command is executed (also no good).

I was wondering if anyone would have any idea of being able to write some kind of custom routine or if there was a known way to "pause" but maintain the ability to issue further commands such as heat the bed (and then be able to resume the print from last known co-ordinates etc)?