Well, I was involved in that market then and I can tell you we all thought those praising NR were bonkers. Put simply, they went on a dash for growth in mortgage assets by lending 125% of value with some very dodgy underwriting on mortgages sourced from 3rd parties, mainly mortgage brokers operating in the self certified sector. ( cf Fanny Mac and Fanny Mae.)
That circle could never be squared and, as you said, they ran out of liquidity.
They also used a charity based tax scam. Needless to say, the spivs who ran it did very nicely, thank you, the CEO buying himself a nice country mansion.