Dear Mel, Welcome!---but I'm sorry about your problems that have led you to this site. And the bowel thing? You are SO not alone.
I was the GI queen of my county, I bet, from age 25 to age 47. I had the invasive tests repeatedly & was told I had a "functional" problem, rather than colitis. I was on various GI meds for many years, but none really helped. Then I started getting new problems (urinary problems, migraines, rashes, pain, fatigue, fevers, anemia, etc.). It took too many years for my local drs. to suspect lupus.
Which leads me to a question: are you sure it's *ulcerative* colitis? If it's NOT, perhaps being treated for the lupus will help your GI issues. Here's a "joke" (on me, alas): I have not had one single GI bout since starting the antimalarial I take for lupus. My best guess is that my GI problems were lupus-driven all along.
Here's some good news: many people with lupus remain pretty mild. The dividing line is really whether a person has major organ involvement (heart, lungs, kidney, CNS, etc.) Antimalarials are the standard therapy where major organs are NOT involved. In contrast, for people with major organ involvement, steroids &/or immunosuppressants are prescribed. And today there are a variety of meds & more medical knowledge than in the past.
If you live in the U.K., look for books by the same Dr. Hughes you cited. He's world-famous & he writes very clearly. But, as you read along, don't assume that everything that is possible in lupus will happen to you. It could even turn out that all that will happen has ALREADY happened.
Anyway, I'm really glad you're on the right track & this close to getting treatment. I hope you keep posting here: we're very good company & have a huge variety of experience. I send you best wishes. Sincerely, Vee