Hi kikidee,
I have never purchased probiotics over the internet, and I am not familiar with that brand -- perhaps others can weigh in on that part. I usually buy whatever has the highest active culture count. And I just buy them at the store -- most health food stores / natural food stores in the US carry live priobiotics in the a regrigerated section. I assume that is the case in the UK?
As far as what's inside them -- you need to check the label, or on the internet, make sure to read through the product materials. A good probiotic will include a variety of the organisms listed below -- some only have 1 or 2, some have as many as 15 or more.
Lactobacillus spp.
Bifidobacterium spp.
Bacillus coagulans
Saccharomyces boulardi
Streptococcus thermophilus
The label or product info should tell you the number of strains -- the number of different types of organisms -- as well as the total number of active cultures, usually in the billions. I usually grad whichever has the highest number of active cultures!
There have been studies looking a the effectiveness of various combinations, but they're mainly inconclusive. Some show modest effect, some show no effect.
There are lots of threads on this forum discussing probiotics -- including a recent one in which people had negative reactions, so definitely look around! Also, there are threads on making yogurt and kefir, if you want to try getting your probiotics the old-fashioned way!
But I think what is most important is to have realistic expectations. Priobiotics can be helpful, but they probably won't cure your CD or be able to replace standard medications to control your disease.