I've not checked recently but there used to be quite an impressive archive on 4oD!

Ah! Here's a few links to get you going...

http://www.channel4.com/programmes/time-team
http://www.channel4.com/programmes/time-team -digs
http://www.channel4.com/programmes/time-team -big-roman-dig
http://www.channel4.com/programmes/time-team -big-royal-dig
And the one you're after is:
http://www.channel4.com/programmes/time-team -specials

I don't work for Channel 4, honest! ;)

G x