James,
Your assumptions are correct. 86611 "Airey Neave" was paired with 86631 and the accident was at Norton Bridge north of Stafford.
There are several photos here:-
http://robsrailphotos.fotopic.net/c61640.html
86631 and 86611 were hauling the 4M53 21:54 Ipswich - Manchester Trafford Park when it ran into the back of the 4M57 21:15 Isle of Grain - Manchester Trafford Park.
Details here at Freightliners website:-
http://www.freightliner.co.uk/news/2003/NR030020a.doc