Go to Nottingham. It's 6th in the UK for Pharmacy, according to Edurank, and KCL is just 21st.
As you say, the Nottingham campus looks very loveable.
Boots the Chemist originated in Nottingham, just saying.
The Complete University Guide shows that average entry grades for the subject are 68% at Nottingham, 66% at KCL. Considering how popular London can be, particularly with international students, this shows me that Nottingham understandably has little difficulty attracting people for this course. Look how recent graduates feel too - according to them, outcomes are higher at Nottingham for this subject. KCL currently has a very good research quality rating, to be fair (91%) but Nottingham is nearly the same (88%) so that's no meaningful difference affecting undergraduate level.