I mentioned it recently on another thread… but I would be quite nervous about going from an airport like CWL to AMS, where there are few flights per day. For whatever reason if the first KLM flight does not run then you b#gger up your whole trip. Far less risky to go the night before IMHO. Or from e.g. LHR with at least one, preferably two flights after your connection, just in case it all goes pear shaped on the day. Just my two cents.