Vitamin D total 43.3 (25 - 50 vitamin D deficiency. Supplementation is indicated) - 800iu D3 daily
The recommended level is 100-150nmol/L. 800iu D3 daily will not raise your level. It is barely a maintenance dose for someone with a reasonable level. You need 5000iu daily for about 6-8 weeks then a retest. When you've reached the recommended level then a maintenance dose of possibly 2000iu daily may be needed, possibly less in the summer.
Your GP probably won't increase your dose, the guidelines won't let him, so if you want to buy your own then my recommendation is
When taking D3 there are important cofactors needed which you can read about here
D3 aids absorption of calcium from food and K2-MK7 directs the calcium to bones and teeth where it is needed and away from arteries and soft tissues where it can be deposited and cause problems. D3 and K2 are fat soluble so should be taken with the fattiest meal of the day.
Magnesium comes in different forms, check here to see which would suit you best and as it's calming it's best taken in the evening
D3 and magnesium need to be taken four hours away from thyroid meds.
Ferritin 23 (15 - 150) - 3 x Ferrous Fumerate daily
This is the normal dose. Take each tablet with 1000mg Vit C to aid absorption and help prevent constipation.
Eating liver once a week, and adding it to any meat dishes will help raise ferritin. It's recommended not to eat more than 200g per week.
Did you also have an iron panel, full blood count and haemoglobin test?
Folate 4.1 (2.5 - 19.5) - folic acid daily
Vitamin B12 226 (190 - 900)
Do you have any signs and symptoms of B12 deficiency
If so pop over to the Pernicious Anaemia Society forum here on Health Unlocked for further advice. Otherwise supplementing with methylcobalamin sublingual lozenges 5000mcg will help improve your B12 level. Anything under 500 can cause neurological problems and the recommended level is very top of range, even 900-1000.