The problem with these adaptors (I have a few) is that the battery in them will not have the same juice as a proper D-size one and the runtime suffers a lot.
LIDL regularly cells D sized rechargeables so I just bought a few (Get the LSD ones), and a suitable charger, again from LIDL and they get used in 2D LED maglites - not the brightest lights but bright enough and solid.
Incidentally, Amazon UK had some good prices on 2/3 D LED maglites.
If weight is not a problem go for the 3D ones as the runtime is a lot better 10 times better !! (better emitter efficiency)
Being maglite, they have not really updated them in a few years, but the one you get will probably be of the newer, slightly more efficient (basic model) ones you see on Mags webpage (amazon shows the original 2011 model specs).