OK, lights MUST go off at night....delineated day and night (light and dark) is extremely important for pretty much all forms of life....24/7 light can actually kill animals. You will need to come up with another way to heat the enclosure at night, such as a ceramic heat-emitter. Your light should never be on more than 16 hours daily.
The UV light is a good one, but it may be spent as far as UV goes...normally these bulbs are good for about 6 months, based on 12 hours per day of usage (to about 2200 hours total use), but burning 24/7, the bulb has likely exceeded its ability to radiate any appreciable UV. Also, since this bulb is a coil UV, it needs to be within 14" of the beardie's basking area, with no glass, plastic, or fine mesh between the bulb and the lizard....and will work best with a good reflector behind it.
28ºC is a bit warm for the cool end of the terrarium...aim for 22ºC-23ºC.