Last 3 mins. in B+W on 'Hammer Collection' R2 DVD - Why???

I just purchased the recent ( Nov. 2006 - Optimum Home Entertainment ) "Hammer Collection" Region 2 DVD and the last scene ( approx. 3 minutes ) after the volcanic eruption is entirely in black and white. What's up with this anyway? I would also like to know about the previous Region 2 DVD release ( July 2002 - Warner Home Video ) and if it truly is the uncut version of the film. This Optimum release runs only 96 minutes and, according to IMDB, the original British release running time is 100 minutes. Amazon UK lists the 2002 Warner DVD release as running only 88 minutes. Can someone who owns this Warner Region 2 DVD of One Million Years B.C. please respond to my questions here? Thanks in advance.