ASD or bust?

Through my own research I've come to the conclusion that although I have some autistic traits I don't think I'd meet the threshold for a clinical diagnosis. It's my belief that I fit the profile for NVLD better.
The trouble being NVLD is scarcely recognised in the UK. I could of course put my eggs all in one basket and push for an ASD assessment but if that fails what then? I've already been told by my local ASD assessment centre they don't cover NVLD, so it's ASD or bust. The trouble being that if it's 'bust' other possibilities won't be explored. I'm not sure it would help much at my advanced age on a practical level. It would be something to throw at those pig ignorant people over the years who have seen me as awkward,demanding,passive aggressive and troublesome etc. To be able to say "Hey this why I am as I am ,and it's not because of any of the intellectually lazy and vapid reasons you pig ignorant people have thrown about. "