I love this show and the DVDs, but I've since learned there was a final episode done in 2013, titled "The Internet is Coming." It's listed as the last episode (7th) of Series 4, but it's not on the DVD; I'm guessing it was created a few years later to tie up the series. Where can I find this episode? Thanks.
I too have searched for the final episode on DVD but to no avail. It is shown on Channel 4 every now and then. I was lucky enough to notice it was on last time and record it onto my SKY box. As I have a DVD recorder, I made my own copy on a DVD+RW disc and edited out the adverts. It's better than nothing and will do me until there is a 10th Anniversary Complete boxset or the like that includes this last, hilarious episode. If you have SKY and have a SKY id, you can sign into NEVER MISS and enter it as a program you don't want to miss. They'll send you an email about 7 days before it comes on so you can set your box to record it.