I'm from the UK too so understand some of your concerns - fact of the matter is, to access DBT over here (considered the gold standard of treatment for BPD), you have to be diagnosed. I don't know anyone who's managed too without, but yes, it's a postcode lottery when it comes to accessing certain therapies and their quality. Is going private an option for you?

Psychiatry isn't a lie. I've had some shockingly bad experiences myself - downright abuse in some incidences. But i acknowledge that i'm not all knowing and sometimes need help. Professionals can assist there. If you don't want to accept that as a possibility then obviously that's your prerogative - i'm just not sure what options you're left with. I would definitely encourage getting an opinion if not the full blown treatment. Non-specific counselling or group therapy might help, but again that would mean going to your GP and possibly being referred somewhere (most likely a CMHT). There is the mental health charity Mind who hold their own groups and appointments. Maybe contact them? They're very good on guidelines and advocacy too. Just to point out, BPD isn't actually classified as a mental illness, but due it's lack of funding/general understanding it's not a diagnosis many want anyway. But again we come back to what having/not having a diagnosis means to you.

To be perfectly honest, you don't strike me as being BPD. All i would say is that if you want help, it's there (well most of the time anyway, but yeah, you can end up fighting for it) - if you don't i hope there are those can support you anyway. All the best.