Having now spotted @Bolter's link, that's a pretty good package.
On frame sizing, you need sufficient stand over to ensure your nuts don't collide with the top tube!! Usually about 3 inches on a mountain bike, therefore, it's better to go for a frame that is slightly under and adjust the saddle and bars to suit than the other way!
That Bizango doesn't look bad, it actually has a half decent fork too, hopefully Halfords will size you properly to the bike, if the bike is too big it's in control of you rather than the other way round. With discounts it's a pretty good deal.Thanks, common sense I suppose! I'm leaning towards the Voodoo, I can go to the local halfords who by all accounts are one of the good ones for bike, have a sit on the bike and a try. I can also get it for a substantial discount between work and a 10% discount code too which obviously helps. As good as the canyon is, it's too good for my needs I think and I don't want to take the chance on sizing when there are no stockists here.