I am posting this because when I was researching buggy boards here I came across two or three threads where people had said that you couldn't attach a bb to a Mothercare Urban Explorer 3-wheeler. I was also given the same advice in a couple of pram shops.
Sorry I can't find those particular posts now, but I just wanted to say - Oh yes you can! - as long as you have the new Universal Attachment bb kit.
the 3-wheeler I've got is the brown and cream model which has 2 very big wheels at the back, bought in early 2002. The handle is very high up so there is room for dd's head inside the square handle space. You need to use the extending arms, but I have found that I can walk pretty normally with the bb attached, ie not kicking it all the time or hunched over.
now I await a chorus of 'everybody knows that'.