Howdens are a trade only company, I used to work for them. They have no website, but are owned by MFI, so some of the ranges obviously are the same.
You can get round the trade only thing by telling them you own houses and they'll usually deal with you. If you go in there as Joe Public, they'll happily give you a catalogue and show you stuff, but you won't get a price list out of them - they do have a full price list they can give out with stupid numbers on it, but no one has ever paid that much for anything in there.
Everything is discounted by at least 40% and kitchens are often reduced by 60% or more depending on how nice the builder is who goes in there.
There are definitely Howdens in the Northwest area, check your phone book