Oh how long would you recommend leaving them if nothing happens as the no water movement worries me a little for oxygen and cleanliness
Ok, this is where knowing about the fish you want to breed is more important than breeding them.
Gouramis are Anabantids which means they have a Labrynth organ to breath atmospheric air just like you and me.
They do not need filtered/ oxygenated water to survive. In fact, the fry are very fragile and water movement (if there is too much) can actually kill the fry.
Professional breeders just use live floating plants in a bare tank with just a heater to breed these fish. That's all that's required.
If the fish have been properly conditioned, they should spawn within a few days of being put together. Feeding should be done sparingly while in the breeding tank and the live plants should help keep the water clean. What little extra food that might get left in the tank by the parents will actually help create or feed the infusoria culture that will be a necessary food for the fry.
A couple of other things to do is to keep the water level at no more than 5"-6" high until the fry are coming to the surface to breath. That usually takes about 6 weeks. The parents don;t need to be removed after spawning as they tend to be a more gentler type of Gourami. (I would suggest removing them once the fry have hatched so you can start feeding the parents a better diet. )
The male may or may not build a nest so you will need to use the fullness of the female as an idicator that the fish have spawned. Unlike other Anabantids (like Bettas) the eggs float so if the male doesn't build a nest, it's no big deal. (This is another reason to use a lot of floating plants in the breeding tank. )
In order to help keep the fry's tanks a little cleaner, you'll want to siphon out any leftover food from the fry and gently siphon water back into the tank. Once the fry are about a month old and large enough to look like fish, you can add a sponge filter onto the tank under gentle air. If you run the sponge filter in another established tank while the fry are growing, it will attract the Beneficial Bacteria so when you put it in the fry's tank, it will already be cycled.
So there you have it.
Hopefully your tank is large enough for doing this in.
Hope this helps