Welcome to ThisIsMS, Sienna.
For a number of reasons, you may be at risk for vitamin D deficiency:
1) Living at a high latitude, i.e., UK (inadequate UVB light)
2) Pigmented skin (in the photos and as Bangladeshi-born, you seem to have darker skin, which requires more exposure to synthesize Vit D)
Since, as a non-UK citizen, you do not qualify for the NHS (From my reading of their guidelines for vitamin D testing and treating, I don't think they are great help anyway.), I encourage you to obtain a private vitamin D blood test (the "25-hydroxy D").
At the very least, read through the information at the California-based GrassrootsHealth website (http://www.GrassrootsHealth.net
). Perhaps there is some way even to take their $70 vitamin D test (which entails putting a few drops of blood on the special blotter card, which is mailed in).
And then there is the fact that MS patients do not respond to vitamin D in the same manner as healthy people:Multiple sclerosis patients have a diminished serologic response to vitamin D supplementation compared to healthy controls.
P Bhargava, et al.https://www.ncbi.nlm.nih.gov/pubmed/26286698
Background: Vitamin D insufficiency is a risk factor for multiple sclerosis (MS), and patients do not always show the expected response to vitamin D supplementation.
Conclusions: Patients with MS had a lower increase in 25(OH)D levels with supplementation, even after accounting for putative confounders.