I'm not sure if you can still do it, but a couple of years ago I bought my AP's over the phone direct with CRO and they posted me vouchers. To my knowledge, that is the only way to buy AP's with the DC discount in the UK.
My DC virtually pays for itself when we buy our AP's (The
only way to to get an AP discount) so everything else is a bonus. Remember - you only need one per household and can get discounts of up to 6 people (if I recall correctly) a day on tickets. The bigger your party, the more it saves!
The discounts at DTD are limited to about 6 of the shops - WoD, Disney at Home, Christmas shop, ummmm...and a couple of the others that are all joined together with the sports shop in and stuff I think and maybe that Pooh shop. Anyhow, it's not all of them...there is a minimum spend of $25 and colletibles like the figurines and the Cels aren't included either. So, it's good, but not perfect and may not be for everyone.
There are however special offers which if you can utilise one of these, then it is really great! For instance, I got a $50 room credit on my cruise, for no other reason than having my DC - no catches. There can also some good discounts on rooms - especially if you don't have an AP, which is really the best way of getting great room rates.
Personally I think DC is worth it....and that's even taking into account that I get many of the same perks being a
DVC'er.
Audrey, you can check out Mousesavers for an idea on what discounts can be gotten with your DC.
Penny