I have asked a similar question on another forum and lots of people say a blu-ray will be fine and will play sacds and dvds as well, even a cheap Sony like the 490 will play them and even 3D DVDs if you want, make sure it has optical output. The Sony is only £80.
Forget about the hifi listen to the music.
A £60 LG BD player from Curry's will still play CDs but the audio won't be in the same street as the Marantz CD player without an external DAC. Also I'm pretty sure just any random blu ray player can't play SA CDs (but yes the Sony does)
DVD Players normally use switching power supply circuits while almost all CDPs use transformers (or toroidal Transformer on better ones) for power supply. The problem of using switching power supply is its noise and it will affect the qulaity of the audio and digital outputs.