I'm trying to do the same on an older model Morphy Richards and after stripping it down it seems easier to replace the whole cable, which is also recommended by MR.
You will almost certainly find that the cable connects to the vac via 2 spade connectors. If like me you dont have the tools or new connectors you won't be able to rewire it yourself unless you buy them.
I'm looking for somewhere that sells spare mains cables with the connectors already fitted for a quick job, if i find anywhere i'll put it up here.
As for dismantaling your model i'm not too sure as each is different but i usualy try unscrewing screws one or two at a time and seeing if the bit i'm wanting to open comes off.