Incomplete/walking Para Bowel Function.

I suspect that your physiotherapist doesn't really understand the problem. In my opinion, keeping your bowels regularly cleaned out is crucial to good health. Also, in my opinion, when I hear non-SCI people talking about "training" your bowels to do anything, they are living in a separate reality to ours. Digital stimulation is how I stay alive, and it minimizes the amount of laxatives I have to take. Yet, my physical therapist at the hospital never once even mentioned it to me. I suffered for six months with nothing but laxatives and suppositories (and twice enemas). I remembered reading a book twenty years earlier that mentioned that paralyzed people have to digitally remove their feces,...gloved hand, lubricant. So, I got one of the latex gloves from the box the nursing home had for aides, and I figured out all-by-myself how to dig out my feces. When I told the administrator that this was what I needed, he threatened to expel me from that nursing home! I transferred to a different nursing home about a month later. Yes, keep your bowels moving. Don't let the physiotherapist stop you.

Hobbit, you might try rotating into your diet some other natural things, in order to reduce the amout of Lactulose that you have to take. Boiled okra with cooked corn and tomato (3 minutes, add butter) tastes good. Prunes, the old standby. A pod (often from Mexico and sold in Mexican supermarkets) called tamarind (tamarindo). An herbal remedy that can be purchased already in capsules called cascara sagrada. Each one of these remedies has its own "personality", so taking them isn't so boring as taking the chemically harsh remedy. Yes, results do vary, but the okra, prunes, and tamarind also have nutritional value.

Excerpt from a nice article:
"Cascara Sagrada, also called Sacred bark and Chittem bark, is an herb derived from the year old bark of Rhamnus purshiana. Native American Indians commonly used Cascara sagrada to treat constipation and upset stomachs.

Taken as an extremely bitter tasting tonic, or in tablet or capsule form, Cascara sagrada is regarded to be a safe laxative that is often employed as a remedy for mild and chronic constipation. Modern herbalists also recommend it as a tonic for the digestive system and to stimulate the liver, pancreas, gallbladder and stomach. It is also considered to be useful in the treatment of jaundice, hemorrhoids and colic...."
nutritionreview.org/2013/10/cascara-sagrada/

Oh, and look! I didn't know this--
"Cascara sagrada can also be used in small doses as a liver tonic and a chelating agent to prevent the occurrence of calcium-based urinary stones."