I got DH tickets for his birthday the other month, and the show was yesterday evening.
I was dubious for myself as I haven't really watched many of the programmes and not really into the whole survival stuff, BUT it was great. Really interesting. He talked about his travels, the people he met and their traditional ways of life, and how he got to know them and live amongst them, finding out more.
Ray Mears talked for about 2 and a half hours, with no interval, followed by about 20 minutes Q&A. He didn't even have a sip of water whilst talking! Was not expecting it to be so lonng and would have been concerned beforehand and known. But he held everyone's attentiion and interest throughout. He did do book signings after but we didn't stay for that as had an hour's drive home (was already 11pm before we left the theatre).
Well worth seeing him if you get the chance!