Been prescription adcal 400iu D3 to take twice daily for vitamin d insufficiency, my levels were 32 nmol/l (in uk) is this too little? I have osteoporosis

Looks good! Your vitamin d level is normal. If the test you had was the 25-hydroxyvitamin d level, this reflects your vitamin d storage. No need to take more. Your doctor should be looking for other reasons why you have osteoporosis at such an early age. By the way, no need to take vitamin d twice daily. Take both pills at once!