I'm sorry to hear about the difficulties you are facing. Could I suggest you research what Paul Bergner says about Vitamin D. There are a number of his videos onhttp://www.312.co/paul+bergner/
which include the podcast about Vitamin D and flu. There have also been several discussions about Vitamin D and absorption on Henriette Kress' medical herbalism email list. You can search the archives of the list on her website.
You say you don't like oily fish? Is that all fish in all forms or just certain ones? Is it the taste you don't like or because they repeat on you? Could you take a dandelion or sweet cecily digestive tonic to improve your digestion before meals to help you process the fish more easily? Could you look at disguising the fish in some way?
The nearest teaching clinic to you used to be Preston. It might be worthwhile searching the National Institute of medical herbalist database to find the nearest qualified herbalists to you and ask if they offer reduced fees for people on low income or if they would consider a barter system. You never know what people might offer until you ask them.
In the mean time, I would suggest you become good friends with all the mineral rich herbs such as nettles, mugwort, violet leaves. All three are easily available now to be wildcrafted. Red clover is also flowering now, so this could also be gathered from a hay field if you have the farmer's permission and you know it hasn't been sprayed with anything nasty.
If you can make your own cider vinegar extraction, this will give you the most mineral dense medium. You can also make overnight cold water macerations with the plant material and drink the resulting liquid either hot or cold. Or you can do Susan Weed's mineral rich tea of 2oz dried plant material to 2 pints boiling water infused in a thermos overnight and drunk the next morning. She favours a mixture of nettles and clover. If you are using fresh herb rather than dried, increase the amount by 1:4.
I hope you are able to source something which is helpful.