i looked up the books as kindle versions, and they appear to be 10 dollars US (me) and 10 pounds UK (you refer to the NHS, so i'm assuming you're in Great Britain?) Not free unfortunately.
So it sounds like you are intending to stay in the relationship and see what you can do to make things better? If so, a great approach is to learn the tools for communication and such. I know what I did to get started was to read through the
LESSONS(they show on the right side of my page under the phrase
Before you can make anything better you must stop making it worse.) That gave me a sense of what I was dealing with--the first thing I had to realize was that what was "normal" for me was not HIS same "normal." My H comes from a very hurt place, and I think that's pretty common for the pwBPD. I know that for him, he had a physically/verbally abusive mother and a fairly absent father, and the pain is evident in his outbursts once I step back from the situation.
I know there are different theories about the origin of BPD (person from abusive background/ genetics/etc) and with my H it's very clear where his originated. That's where their very young emotional makeup comes from. It helped me understand what is common for a pwBPD by reading
Lesson 1 "Understanding your partner's behaviors" . I didn't realize how my reactions could make things worse, but danged if they don't! That's where
Lesson 2 "Understanding your role in the relationship" comes in.
And in
Lesson 3, "Tools: Communication" where i'm spending a lot of time off and on, we're given tools that help us with the goal of helping the situation rather than hindering.
Unfortunately, someone who has a really hard time being wrong isn't likely to hear they should get therapy (personal experience!) And we can only change OUR end of the relationship, honestly, since we can only change ourselves.
I'm starting to see some changes in our communication as I've truly started understanding how to not just defend myself (I hate when someone is saying i'm a way that I know I am not!) and how to make him feel heard without just feeling slaughtered myself. So many good skills to be learned on this site!
Dig around and enjoy the process, it's pretty interesting. And if nothing else, we learn skills that will help us deal with all kinds of people in our lives!

Hope i'm not just repeating stuff you've already read, that was just such a good learning place so I could wrap my head around what i'm dealing with.

DF99