Hi - thanks very much for posting the question. I looked into this as well recently as I’m near Aberdeen. In the end I decided to train to London and take SQ from LHR. The other thing (as well as price) that put me off was the timing of the eastbound flights. Because the SQ flight leaves AMS late morning, with the 1hr time zone change the only same day flight was at around 6am from ABZ. Alternatively an overnight in AMS.

KL have high charges for baggage whereas SQ include free baggage for non-elites.

(I also considered flying the whole way with KL but honestly SQ intercontinental is way better IMO and KL is 3-4-3 on the 777 in Y making it for me (a non-elite) either cramped or expensive!!)