Forum member, JaneV was able to attend and has given us some of her impressions. Beware spoilers! I thought I'd post some of her comments about the "Any Human Heart" Preview Screening and Q&A, here, though.
Jane first mentions that there was "wine, canapes and 90 minutes of delight. C4 did us proud!"
William Boyd was present to do the Q&A. The audience saw the first 90 minute episode + a short snapshot of the rest of the production. Matthew's part of the production begins around 45 mins (maybe a little less) into the first part. The story is told as a series of flashbacks.
Finally, there are hints that C4 will show Any Human Heart on a Sunday in November, but not necessarily on the 14th of November.