otv
Your looking for an odd spec cable - very odd when you look at your kit list.
Any Fully Wired (standard) SCART cable will deliver RGB + LR Audio from your SCART source to the Media Box on your TV.
If you want an improvement in image quality you could go with an RGB Only or RGB+LR Audio Only cable - a bit more money but worth the extra.
RGB and YUV 'Component' are not interchangeable without some active signal processing - if your wanting to connect your RGB SCART equipped source to the YUV Input on the TV Media Box you'll require a JS Technology RGB to YUV converter plus cables; a lot of expenses for little return I'd say.
If your SCART equipped Source can Output YUV over SCART (a very few can) then its easy enough to provide you with a correctly wired SCART to 3RCA cable for YUV connectivity.
Best regards
Joe