First of all, be sure that your UVB light sources are fresh and adequate. A good quality mercury vapor lamp is a fairly good way to try to simulate sunlight and aid in calcium absorption. As are the more popular brands of UVB fluorescent lamp. I usually use both in each of my enclosures although most of my herps are in outdoor caging when weather permits. Just keep in mind that the fluorescent lamps should be checked/replaced annually if not sooner. It is most important that these UVB lighting sources are the proper distance from the surface where your uro(s) spend most of its waking hours. Most manufactures will state the proper distances on the package.
Also, be sure to put them on a regime of preventative maintenance supplementation. In your case I suggest a good calcium/supplement/vitamin source with D-3 added. I personally use miner-all (I). I would also recommend a great calcium 'quick fix' which can be administered orally. This is calcium glubionate (neo cal-glucon) which you can order at most pharmacies. It sounds like your ornates have had MBD since you originally got them. If the bumps on their spinal column have re appeared, that means that the MBD is re occurring. This can be a deadly disease of not taken care of quickly. If it were my animals, I would start them on this therapy with a regime of 0.2 cc of the calcium glubionate for each 100 grams of animal weight ASAP. Or, you can simply offer them a drop or two (depending on the uro's weight) and give them this amount twice a day for the first week and every other day for the second week. Continue through the third and fourth week but reduce the oral dose frequency to every two or three days. By the end of the first month you should begin to see a reduction of the spinal bumps. Hopefully they'll disappear completely in time. Once they seem to be back on trak You can offer them the calcium syrup once every month throughout their lives. Once MBD (metabolic bone disease) takes hold, it may never go away but can pretty much be controlled with the proper therapy depending on the advancement of the disease.
Remember, be sure to keep a close check on your UVB lighting source including mounting distance and keep up the calcium supplementation at regular intervals or when you feel it's necessary.
Good luck with your ornates.
Sorry for the long post,
John