At £400 you would think it would be very simple and intuitive
to use???
Its simplicity and ease of use depend upon how well you understand all of your system's remote control commands, how they interact when you turn the system on and off and change inputs, and how well you program the remote. The £400 price is what it takes to make a remote that is capable of doing this with incredible flexibility and features. Unfortunately, "capable" and "simple" are usually at odds with one another, as are "capable" and "cheap."
Yes, the codes have to be learned, but you don't have to do it all.
The Pronto NG files section of this site has many many files that someone has already learned and uploaded to share. These usually are not just commands, but also buttons, that is to say artwork, that these people have either created, borrowed, or just used from the gallery in the program.
The Pronto NG files can be used in a Marantz, too.
Some components might not be in the Pronto NG section, but might be in the Original Pronto section. If this is the case, you will need to download the original Pronto software and learn how to open the files so you can copy and paste those learned commands into your Marantz file.
There can be a lot to it, but you will probably make a lot of progress just by looking for your model numbers, or similar model numbers, in the Pronto NG Files section, and taking it from there.
Also, with those cheaper remotes that were so easy to program, wasn't there always some critical button missing? I remember the first one I used had no TV Input button; later ones had no MENU button; something was always incomplete.
And if you had a TV/VCR combo, you could use a VCR code to make the remote work perfectly, except VCRs don't have volume commands, so you were out of luck there....