I think you have very strong chances imo, honestly. your supercurriculars are proper solid it's just, like are you absolutely not able to get the B up to an A predicted my guy? A*AB does average out to triple A but I'm unsure on how kcl view applications that have been made with predicteds lower than the minimum entry requirements; I know about scenarios whereby one has missed the offer for example (i.e. if someone missed by a maximum of 2 grades and got ABB for this course they would still have a high chance of being accepted) but I can't remember on how they are with predicteds meeting the reqs,
I would, say that it would be fine? perhaps see if you could send them a short email with regards to this or reach out to a student rep on the live chat (I think there is one iirc)