Having listened to part of the beginning, then a bit more further on, I came in around the middle and listened to the end. Apart from the fact that A C Grayling Is a brilliant academic, has an excellent speaking voice and comes across as a very nice person, I realise in fact that I did know a bit more about Wittgenstein than I thought I did!
I went out about 8:30, while the sun was shining, but far too many large puddles to do my usual walk, so was back here about 9:20 ... just in time for there to be a heavy shower a few minutes later.